Vertical heat treatment system, method for controlling vertical heat treatment system, and method for transferring object to be treated

ABSTRACT

There is provided a vertical heat treatment system capable of simplifying the structure of various mechanisms in the vicinity of an opening which is formed in a partition wall separating a housing-box transfer area from a treating-object transfer area (a wafer transfer area), and of contributing to space saving, when an object to be treated is carried in the vertical heat treatment system through the opening to carry out a predetermined treatment.  
     In a vertical heat treatment system for carrying an object W to be treated, which is housed in a treating-object housing box  2  closed by an opening/closing lid  10 , in a treating-object transfer area  46  via an opening  28 , which is formed in a partition wall  26  separating a housing-box transfer area  44  for transferring the treating-object housing box from the treating-object transfer area  46  in an atmosphere of an inert gas, to carry out a predetermined treatment, a standby box transfer means  60  is provided in the housing-box transfer area for holding a treating-object housing box, which houses therein the next object to be carried in the treating-object transfer area, in the vicinity of the opening to cause the treating-object housing box to stand by. Thus, when the object to be treated is carried in via the opening of the partition wall, which separates the housing-box transfer area from the treating-object transfer area (wafer transfer area), to carry out a predetermined treatment, the structure of various mechanisms in the vicinity of the opening is simplified, and the space is saved.

TECHNICAL FIELD

[0001] The first invention relates generally to a vertical heattreatment system utilizing a treating-object housing box for airtightlyhousing therein objects to be treated, such as semiconductor wafers.

[0002] The second invention relates to a vertical heat treatment systemused for carrying out a treatment, such as oxidation, diffusion,annealing or CVD, for objects to be treated, such as semiconductorwafers, and a method for controlling the same.

[0003] The third invention relates to a vertical heat treatment systemfor heat-treating objects to be treated, and a method for transferringobjects to be treated, and more specifically, relates to a vertical heattreatment system and treating-object transferring method which arecapable of aligning a holder for holding objects to be treated.

[0004] The fourth invention relates to a heat treatment system for usein steps of fabricating a semiconductor device or the like.

BACKGROUND ART

[0005] The background of the first invention will be described below.

[0006] In general, in order to fabricate a semiconductor integratedcircuit, such as an IC or LSI, various deposition, oxidation anddiffusion, and etching processes are repeatedly carried out for asemiconductor wafer. When the respective processes are carried out, itis required to transfer the semiconductor wafer between correspondingsystems. In this case, as well known, in order to improve the yields, itis required to prevent particles and natural oxide films from adheringto the surface of the semiconductor wafer. Therefore, with the increaseof the request for high scale down and high density integration, aclosed treating-object housing box tends to be used for transferring thewafer. As shown in FIGS. 5 and 6, a treating-object housing box 2 has anopening portion 4 on one end thereof, and a substantially semi-circularbox vessel 6 on the other end thereof. Multistage supporting protrusions8 are provided on the inner wall of the box vessel 6, and the peripheralportions of semiconductor wafers W are mounted and supported thereon, sothat the semiconductor wafers W can be housed therein on multiple stagesat substantially even intervals. On the ceiling portion of the boxvessel 6, a gripping handle 24 for holding the whole vessel is provided.Usually, one box can house therein about 25 or 13 wafers.

[0007] A rectangular hollow plate-shaped lid 10 is detachably mounted onthe opening portion 4 of the box vessel 6. The interior of the boxvessel 6 is evacuated in an airtight state to some extent, to be in anatmosphere of an inert gas, such as N₂ gas, so that the wafers W housedtherein do not contact outside air as much as possible.

[0008] The lid 10 is provided with two locking mechanisms 12. Byreleasing the locking mechanism 12, the lid 10 can be removed from theopening portion 10.

[0009] Specifically, as shown in FIG. 7, each of the locking mechanisms12 has a rotatable disk-shaped locking plate 14 at the substantiallycenter of the lid 10 in height directions. The locking plate 14 isformed with an elongated recessed key groove 16. Above and below thelocking plate 14, there are provided a pair of rising and setting pins20, each of which is connected to an arm 18 as a crank mechanism forconverting a circular motion into a linear motion. By rotating thelocking plates 14 by 90 degrees in normal and reverse directions, theupper and lower rising and setting pins 20 rise and set in verticaldirections.

[0010] During locking, as shown in FIG. 6, the tips of the rising andsetting pins 20 are inserted into and engaged with pin holes 22, whichare formed in top and bottom edge portions for defining the openingportion 4 (only the bottom edge portion is shown in FIG. 6), to preventthe lid 10 from being removed from the opening portion 4. Therefore, ifkey members (not shown) are engaged with the corresponding key grooves16 to be rotated by 90 degrees from a locked state shown in FIG. 7(A) toretract the rising and setting pines 20 by a distance ΔL as shown inFIG. 7(B) to pull them out of the pin holes 22 (see FIG. 6), the lid 10is in an unlocked state.

[0011] In general, the above described housing box 2 is automaticallytransferred in a treatment system which includes an automatic transfermechanism for the housing box, a stock region for temporarily stockingtherein the housing box, and a treatment unit for treating semiconductorwafers. In addition, key members 26 are operated by automaticapparatuses having them, so that the lid 10 of the housing box 2 isautomatically detached and attached by the above described process.

[0012] For example, such a treatment system is disclosed in JapanesePatent Laid-Open No. 4-180213, Japanese Patent Laid-Open No. 8-279546,Japanese Patent Laid-Open No. 11-274267, and the applicant's priorapplication (Japanese Patent Application No. 11-201000). To the interiorof the system, an inert gas, such as N₂ gas, or clean air having a highcleanliness factor is supplied.

[0013] Specifically, the interior of the above described treatmentsystem is airtightly separated into a housing-box transfer area forreceiving and temporarily stocking the housing box therein, and a wafertransfer area for transferring semiconductor wafers, which are taken outof the housing box after opening the housing box, to a wafer boat or thelike to actually carry out a treatment. The housing-box transfer area isfilled with clean air, and the wafer transfer area is filled with aninert gas, such as N₂, for preventing natural oxide films from beingproduced.

[0014] The partition wall for separating both areas from each other hasa door capable of being open and closed. This door is provided with oneor two opening portions. The housing box is set so as to tightly contactthe opening portions. Then, the housing box lid and the door are removedfrom the wafer transfer area to take shelter. In this state, thesemiconductor wafers are fed into the wafer transfer area.

[0015] Referring to FIGS. 8 and 9, the state at this time will bedescribed below.

[0016] In the case of an example of a conventional system shown in FIG.8, two stages of upper and lower mounting tables 30A and 30B capable ofbeing integrally moved in vertical directions are provided on the sideof the housing-box transfer area of the opening portion 28 of apartition wall 26, and a treating-object housing box 2 is mountedthereon to be fixed. An opening/closing mechanism 34 for removing thelid 10 and a door 32 for opening and closing the opening portion 28 isprovided for substantially simultaneously removing the lid 10 and thedoor 32 and for causing them to take shelter upwards or downwards whileholding them. The opening/closing mechanism 34 is provided with a keyportion (not shown) which is inserted into the key groove shown in FIG.6 to be rotated to carry out locking and unlocking.

[0017] After the carrying-out of the wafers in one of the housing boxesis completed, the lid 10 and the door 32 are mounted again. Thereafter,the mounting tables 30A and 30B are caused to integrally slide upwardsin, e.g., the shown embodiment, and the wafers are carried out of thehousing box 2, which newly faces the opening portion 28, in the samemanner as that described above.

[0018] Furthermore, the reason why the two housing boxes 2 are thus setis that the wafer carrying-in/out efficiency is improved.

[0019] On the other hand, in the case of an example of a conventionalsystem shown in FIG. 9, the partition wall 26 is provided with upper andlower openings 28A and 28B which are provided with doors 32A and 32B foropening and closing them, respectively. Inside of the housing-boxtransfer area of the openings 28A and 28B, mounting tables 30A and 30Bare fixedly mounted, respectively. Inside of the wafer transfer area ofthe openings 28A and 28B, two opening/closing mechanisms 34A and 34B areprovided so as to correspond to the openings 28A and 28B, respectively.In the same manner as that described above, the lid 10 and the door 32Aor 32B are removed from the housing box, which is set on each of theopenings 28A and 28B, by means of the opening/closing mechanisms 34A and34B. Furthermore, these opening/closing mechanisms are disclosed inJapanese Patent Laid-Open No. 11-274267, which has been described aboveas the prior art, and so forth.

[0020] By the way, in the above described examples of conventionalsystems, two housing boxes can be set in the vicinity of one or twoopenings, so that it is possible to fed the wafers into the wafertransfer area to greatly improve the transfer efficiency of the wafersto the wafer boat.

[0021] However, in the case of the example of the conventional systemshown in FIG. 8, the two mounting tables 30A and 30B are provided so asto be slidable in vertical directions. Therefore, there is a problem inthat it is required to ensure a large space for three housing boxes inthis portion.

[0022] In the case of the example of the conventional system shown inFIG. 9, it is sufficient to provide a space for only two housing boxes.However, in this case, there is a problem in that it is required toprovide two opening/closing mechanisms 34A and 34B which have acomplicated structure and which are relatively expensive, so that thecosts are high.

[0023] In particular, in the case of the opening/closing mechanisms 34Aand 34B shown in FIG. 9, the structure must be complicatedly devised inorder to avoid the interference of the opening/closing mechanisms witheach other, so that higher costs are caused.

[0024] The background of the second invention will be described below.

[0025] In the fabrication of semiconductor devices, various treatments,such as oxidation, diffusion and CVD, are carried out with respect tosemiconductor wafers serving as objects to be treated. As systems forcarrying out such treatments, so-called vertical heat treatment systemsare widely utilized.

[0026] As such a vertical heat treatment system, from the standpoint ofthe improvement of throughput, there is known a vertical heat treatmentsystem which uses two wafer boats serving as holders for holding aplurality of semiconductor wafers and wherein semiconductor wafers aretransferred with respect to one wafer boat while heat treatment iscarried out with respect to the other wafer boat.

[0027] The conventional heat treatment system has a housing which isseparated into front and rear portions by a partition wall to define acarrier transfer area and a loading area in which a vertical heattreatment furnace having an opening in its bottom is provided. Theloading area includes: a boat elevator which is a lifting mechanismmoved in vertical directions for carrying a wafer boat in and out of theheat treatment furnace; a holder mounting portion comprising two boatmounting portions which are arranged in the front and rear portions ofone side portion of the housing; a boat transfer mechanism which is aholder transfer mechanism for transferring the wafer boat between theboat mounting portion and the boat elevator; and a wafer transfermechanism which is a treating-object transfer mechanism for transferringsemiconductor wafers with respect to the wafer boat supported on theboat mounting portion.

[0028] This vertical heat treatment system has a motion space region inwhich the wafer transfer mechanism and the boat transfer mechanismoverlap with each other. When the semiconductor wafers are transferred,the boat transfer mechanism is moved to a sheltered position below themotion space region, and when the wafer boat is transferred, the wafertransfer mechanism is moved to a sheltered position above the motionspace region.

[0029] The sheltered position of the wafer transfer mechanism is thusarranged upwards in the vertical heat treatment system with the abovedescribed construction. Therefore, when the wafer boat is carried out ofthe heat treatment furnace, the wafer transfer mechanism is easy to havethe influence of heat from the bottom end opening of the heat treatmentfurnace and the wafer boat after the heat treatment, and the temperatureof the wafer transfer mechanism at the sheltered position sometimesreaches to 150° C., so that it is difficult to stably operate the systemfor a long term due to the failure of the control apparatus in the wafertransfer mechanism and so forth.

[0030] In recent years, it has been also requested to increase thediameter of the semiconductor wafer in order to improve the yields ofchips per one semiconductor wafer. For example, it has been requestedthat a semiconductor wafer having a diameter of 12 inches (300 mm) isheat-treated.

[0031] However, with the increase of semiconductor wafers, the width,length and height of the vertical heat treatment system increase, sothat the floor area and ceiling height for the installation of the heattreatment system also increase. Therefore, the production costs andmaintenance costs of the vertical heat treatment system increase, sothat it is required to miniaturize the vertical heat treatment system.

[0032] The background of the third invention will be described below.

[0033] As one of systems for heat-treating objects to be treated, suchas semiconductor wafers (which will be hereinafter referred to aswafers), in a semiconductor fabricating processes, there is a verticalheat treatment system for carrying out a batch treatment. In thissystem, a plurality of wafers serving as objects to be treated are heldon a holder (boat) while being stacked, and this holder is carried in avertical heat treatment furnace for carrying out heat treatment, e.g.,CVD (Chemical Vapor Deposition) and oxidation.

[0034] The vertical heat treatment system has a holder mounting portion(holder supporting mechanism, boat stage) for supporting thereon theholder. The objects to be treated are transferred to and held in theholder which is supported on the holder mounting portion. Thereafter,the holder mounting portion, in which the objects to be treated areheld, is housed in the heat treatment chamber of the vertical heattreatment system, and the objects to be treated are heat-treated.

[0035] When the objects to be treated are heat-treated, the positionalrelationship between the interior of the heat treatment chamber and theobjects to be treated is important. Since the temperature distributionand the concentration distribution of atmospheric gas exist in the heattreatment chamber, it is required to arrange the objects in the heattreatment chamber so that the centers of these distributions correspondsto the center of the wafers serving as the objects to be treated. If theheat treatment is carried out in a state that these centers do notcorrespond, the thickness values of the films formed on the objects areununiform.

[0036] In order to make the positional relationship between the heattreatment chamber and the objects constant, it is effective to make thepositional relationship between the holder and the objects constant.

[0037] There are some cases where the position shift occurs when theholder (boat) is mounted on the holder mounting portion (holdersupporting mechanism, boat stage), and there is some possibility thatthe position error causes errors in the position relationship betweenthe objects and the holder when the objects are transferred.

[0038] The background of the fourth invention will be described below.

[0039] As one of systems for heat-treating objects to be treated, suchas semiconductor wafers (which will be hereinafter referred to as“wafers”), in a semiconductor fabricating processes, there is a verticalheat treatment system for carrying out a batch treatment. In thissystem, a plurality of wafers are held on the multiple stages of aholder, such as a wafer boat, and this holder is carried in a verticalheat treatment furnace for carrying out various heat treatments, such asdiffusion, oxidation or CVD

[0040] (Chemical Vapor Deposition).

[0041] In recent years, in order to surely inhibit contamination due toparticles and natural oxide films on the wafers from being produced in aregion called a loading area for carrying wafers in and out of the heattreatment furnace in such a vertical heat treatment system, a closedtype system or the like has been put to practical use wherein theloading area is separated as an airtight region which is isolated fromoutside air, to form an atmosphere of an inert gas, such as nitrogengas, to carry the wafers in and out.

[0042] By the way, the heated wafers after the heat treatment arecarried in the above described loading area from the heat treatmentfurnace, and the temperature of the loading area is high, so that it isrequired to provide a cooling mechanism. This cooling mechanism isprovided for mainly protecting a filter or the like for purifying theinterior of the area, from heat. Therefore, in view of the suppressionof the flying of particles in the area, the cooling mechanism isprovided in the vicinity of an intake hole, i.e., relatively below theloading area.

[0043] However, the above described conventional cooling mechanism hasthe following problems. That is, in recent years, in order to furtherimprove the productivity of semiconductor devices, the size of wafersserving as objects to be treated is being changed from a diameter of 8inches (about 200 mm) to a relatively large diameter of 12 inches (about300 mm). When wafers of this large size are carried out of alarge-diameter heat treatment furnace which heat-treated the wafers, alarge amount of heat is emitted from a throat, and the temperature ofthe loading area suddenly rises due to a large amount of radiationsimultaneously emitted from the large-diameter wafers and the waferboat, so that there is a problem in that various control parts includingelectrical parts provided in the area are damaged.

[0044] Moreover, this phenomenon that the temperature in the loadingarea suddenly rises to the high temperature causes a more seriousproblem in the case of the closed type (inert gas purging box type)system for circulating an inert gas in the area.

DISCLOSURE OF THE INVENTION

[0045] The first invention has been made to effectively solve the abovedescribed problems. It is an object of the first invention to provide avertical heat treatment system capable of simplifying the structure ofvarious mechanisms in the vicinity of an opening which is formed in apartition wall separating a housing-box transfer area from atreating-object transfer area (a wafer transfer area), and ofcontributing to space saving, when an object to be treated is carried inthe vertical heat treatment system through the opening to carry out apredetermined treatment.

[0046] According to the first invention, there is provided a verticalheat treatment system for carrying an object to be treated, which ishoused in a treating-object housing box closed by an opening/closinglid, in a treating-object transfer area via an opening, which is formedin a partition wall separating a housing-box transfer area fortransferring the treating-object housing box from the treating-objecttransfer area in an atmosphere of an inert gas, to carry out apredetermined treatment, wherein standby box transfer means is providedin the housing-box transfer area for holding a treating-object housingbox, which houses therein the next object to be carried in thetreating-object transfer area, in the vicinity of the opening to causethe treating-object housing box to stand by.

[0047] Thus, when objects to be treated are carried out of onetreating-object housing box into the treating-object transfer area viathe opening of the partition wall or the like, the standby box transfermeans causes the next treating-object housing box to stand by in thevicinity of the opening (mounting table), and immediately after theobjects in the last treating-object housing box are completely carriedout, the treating-object housing box during standby can be set in theopening to carry objects out. Therefore, the carrying and transfer ofthe objects in and to the treating-object transfer area can be quicklyand efficiently carried out in a space saving state without causing thestructure to be so complicated.

[0048] In this case, for example, in the housing-box transfer area,there may be provided a stocker portion for temporarily storing thereinthe treating-object housing box, and a box transfer arm for transferringthe treating-object housing box in the stocker portion to a mountingtable which is provided in the opening.

[0049] In addition, an opening/closing door may be provided in theopening, and an opening/closing mechanism for removing theopening/closing door and the opening/closing lid to cause theopening/closing door and the opening/closing lid to take shelter may beprovided in the treating-object transfer area.

[0050] The second invention has been made in view of the above describedcircumstance. It is an object of the second invention to provide avertical heat treatment system having a small influence of heat on atreating-object transfer mechanism when a holder is carried out of aheat treatment furnace.

[0051] It is another object of the second invention to provide a smallvertical heat treatment system having a high throughput.

[0052] It is a further object of the second invention to provide acontrol method capable of stably operating such a vertical heattreatment system.

[0053] According to the second invention, a vertical heat treatmentsystem comprises: a lifting mechanism which is vertically moved forcarrying a holder, in which an object to be treated is held, in and outof a heat treatment furnace; a holder mounting portion for mountingthereon the holder to transfer the object; a holder transfer mechanismfor transferring the holder between the lifting mechanism and the holdermounting portion; and a treating-object transfer mechanism fortransferring the object to the holder which is supported on the holdertransferring portion, the treating-object transfer mechanism having amotion space region which overlaps with a motion space region of theholder transfer mechanism, wherein the treating-object transfermechanism comprises a swivel arm supported so as to be rotatable about avertically extending rotation center shaft, and a transfer head providedon the tip portion of the swivel arm so as to be rotatable on ahorizontal plane, and further comprises driving means having thesheltering function of moving the transfer head of the treating-objecttransfer mechanism on the horizontal plane along the outer peripheraledge of the lifting mechanism, which is positioned at a lower position,to cause the transfer head to take shelter on a side face portion of ahousing.

[0054] In the vertical heat treatment system according to the secondinvention, the sheltering function of the driving means of thetreating-object transfer mechanism preferably causes the transfer headof the treating-object transfer mechanism to revolve around the rotationcenter shaft of the swivel arm while causing the transfer head itself torotate on its axis in the opposite direction to the direction ofrotation of the transfer head, to cause the transfer head to takeshelter on the side face portion in the housing.

[0055] In addition, in the vertical heat treatment system according tothe second invention, the sheltering function of the driving means ofthe treating-object transfer mechanism preferably operates the transferhead of the treating-object transfer mechanism from a state that thetransfer head is positioned at a reference position in its motion spaceregion.

[0056] Moreover, in the vertical heat treatment system according to thesecond invention, the driving means of the treating-object transfermechanism preferably comprises a stretching mechanism for rotating theswivel arm, and a belt transmission mechanism for transmitting therotational motion of the swivel arm to the transfer head. In this case,the reference position in the motion space region may be set by a pulleyratio in the belt transmission mechanism.

[0057] According to the second invention, there is provided a method forcontrolling a vertical heat treatment system comprising: a liftingmechanism which is vertically moved for carrying a holder, in which anobject to be treated is held, in and out of a heat treatment furnace; aholder mounting portion for mounting thereon the holder to transfer theobject; a holder transfer mechanism for transferring the holder betweenthe lifting mechanism and the holder mounting portion; and atreating-object transfer mechanism for transferring the object to theholder which is supported on the holder transferring portion, thetreating-object transfer mechanism having a motion space region whichoverlaps with a motion space region of the holder transfer mechanism,the treating-object transfer mechanism comprising a swivel arm supportedso as to be rotatable about a vertically extending rotation centershaft, and a transfer head provided on the tip portion of the swivel armso as to be rotatable on a horizontal plane, wherein the transfer headof the treating-object transfer mechanism is moved on the horizontalplane along the outer peripheral edge of the lifting mechanism, which ispositioned at a lower position, to take shelter on a side face portionof a housing, when the holder transfer mechanism is operated.

[0058] In the control method according to the second invention, thetransfer head of the treating-object transfer mechanism may be caused torevolve around the rotation center shaft of the swivel arm while thetransfer head itself is caused to rotate on its axis in the oppositedirection to the direction of rotation of the transfer head, to takeshelter on the side face portion in the housing.

[0059] According to the vertical heat treatment system of the secondinvention, when the holder is transferred, the treating-object transfermechanism takes shelter on one side face portion of the housing, so thatthe holder during transfer does not interfere with the treating-objecttransfer mechanism. In addition, the treating-object transfer mechanismtakes shelter on the same plane as that of the lifting mechanism whichis positioned at the lower position, so that the influence of heat fromthe heat treatment furnace and so forth can be very small.

[0060] In addition, since the space required for the sheltered operationcan be reduced by allowing the transfer head of the treating-objecttransfer mechanism to move along the outer peripheral edge of thelifting mechanism, the holder mounting portion and so forth can bearranged at a high spatial utilization factor, so that the whole systemcan be miniaturized while maintaining a high throughput.

[0061] According to the control method of the invention, it is possibleto surely prevent the holder during transfer from interfering with thetreating-object transfer mechanism, and the influence of heat from theheat treatment furnace and so forth can be very small, so that it ispossible to stably operate the vertical heat treatment system.

[0062] In addition, since the transfer head of the treating-objecttransfer mechanism can take shelter in a relatively small space, theholder mounting portion and so forth can be arranged at a high spatialutilization factor, and the whole system can be miniaturized whilemaintaining a high throughput.

[0063] In view of the foregoing, it is an object of the third inventionto provide a heat treatment system having a holder supporting mechanismcapable of mounting an object to be treated at a predetermined position.

[0064] In order to accomplish the above described object, a verticalheat treatment system according to the third invention has a holdersupporting mechanism comprising: a holder mounting table for mountingthereon a holder for holding a plurality of objects to be heat-treated,in a stacked state; and a holder position adjusting mechanism includinga plurality of protruding portions corresponding to the shape of abottom plate of the holder, and a distance varying mechanism for varyingthe distance between the plurality of protruding portions.

[0065] Since the holder supporting mechanism has the holder positionadjusting mechanism for adjusting the position of the holder, thepositioning of the holder can be easily carried out after the holder ismounted on the holder mounting table. As a result, it is possible toprecisely transfer the objects to the holder. Furthermore, thispositioning can be carried out by changing the distance between theplurality of protruding portions corresponding to the shape of thebottom plate of the holder.

[0066] The holder supporting mechanism may further comprise a slidingmechanism for allowing the holder mounting table to move on a planealong a holder mounting surface of the holder mounting table. By thesliding mechanism, the holder mounting table can easily move with theholder mounting table, and the positioning of the holder can be easilycarried out.

[0067] The holder supporting mechanism may further comprise a returningmechanism for returning the holder mounting table to a predeterminedposition, the returning mechanism including biasing means for biasingthe holder mounting table in a different direction on a plane along aholder mounting surface of the holder mounting table.

[0068] Thus, it is possible to return the position of the holdermounting table before the transfer of the holder, and it is possible toensure the movable range of the holder mounting table during thepositioning of the holder.

[0069] According to the third invention, there is provided a method fortransferring an object to be treated, the method comprising: a mountingstep of causing a holder, which serves to hold a plurality of objects tobe heat-treated in a stacked state, to be mounted on a holder mountingtable; a positioning step of moving the holder, which is mounted on theholder mounting table at the mounting step, together with the holdermounting table, on a plane along a holder mounting surface of the holdermounting table to position the holder at a predetermined position; atransfer step of transferring the objects to the holder which ispositioned at the positioning step; and a returning step of removing theholder, to which the objects are transferred at the transfer step, fromthe holder mounting table to return the holder mounting table to apredetermined position.

[0070] Since the position of the holder is adjusted before the objectsare transferred, the precision of the position is improved when theobjects are transferred to the holder. In addition, since the positionof the holder mounting table is returned after removing the holder towhich the objects are transferred, it is easy to ensure the precision ofadjustment of the position of the holder.

[0071] The fourth invention has been made to solve the above describedproblems. It is an object of the fourth invention to provide a heattreatment system having excellent cooling effects in a carrying-in/outregion of a heat treatment furnace in and out of which an object to betreated is carried.

[0072] It is another object of the fourth invention to provide a heattreatment system having excellent cooling effects while inhibiting thecarrying-in/out region from being contaminated by particles.

[0073] In order to accomplish the above described objects, according tothe fourth invention, a heat treatment system comprises: a heattreatment furnace for heat-treating an object to be treated; a throatwhich is provided in the heat treatment furnace for carrying the objectin and out; and a cooling mechanism for cooling the vicinity of thethroat.

[0074] Since the heat treatment system according to the fourth inventioncools the vicinity of the throat of the heat treatment furnace, heatemitted from the throat of the heat treatment furnace and be removed andthe heated objects can be cooled, when the objects heated to a hightemperature in the heat treatment furnace are, for example, carried out.Thus, it is not feared that the temperature in the carrying-in/outregion carrying the objects in and out of the heat treatment furnace maysuddenly rise, so that it is possible to inhibit control parts and soforth provided in the carrying-in/out region from being damaged by heat.

[0075] In the heat treatment system according to the fourth invention,the cooling mechanism may comprise a ventilating unit having aventilating port for sending a cooling fluid toward the vicinity of thethroat, and a heat exchanger arranged so as to face the ventilating portin the vicinity of the throat.

[0076] This heat treatment system according to the fourth invention caneffectively heat, which is emitted from the throat of the heat treatmentfurnace, by the ventilating unit for sending the cooling fluid to theobjects, which are carried out while being heated, and by the heatexchanger, such as a radiator, for removing heat of thetemperature-raised cooling fluid in the vicinity of the throat.

[0077] Moreover, in the heat treatment system according to the fourthinvention, the cooling mechanism may further comprise an intake fan forsucking the cooling fluid in the vicinity of the throat over the heatexchanger.

[0078] The heat treatment system according to this invention canpositively draw the temperature-raised cooling fluid in the vicinity ofthe throat into the heat exchanger by the intake fan to effectivelyremove the heat. Moreover, in the heat treatment system according tothis invention, the intake fan is arranged downstream of the heatexchanger in the flow of the cooling fluid, so that the cooling fluidpassing through the heat exchanger to be cooled is sucked by the intakefun. Thus, it is possible to inhibit the intake fun from being damagedby heat.

[0079] Moreover, in the heat treatment system according to the fourthinvention, the cooling mechanism may further comprise: a duct forforming a circulating path for the cooling fluid between the intake funand the ventilating unit so that the cooling fluid sucked by the intakefan returns to the ventilating unit; a filter, provided in the duct orthe ventilating unit, for purifying the cooling fluid which is sent bythe ventilating unit; and an intake port which is formed on the duct atleast upstream of the filter so that the cooling fluid sent by theventilating unit is sucked at a different position from a position atwhich the cooling fluid is sucked by the intake fun.

[0080] This heat treatment system according to the fourth invention canbe used for purifying and circulating the cooling fluid for cooling thevicinity of the throat, so that this heat treatment system can be usedas a closed type system for blocking the carrying-in/out region carryingthe objects in and out of the heat treatment furnace from outside airand for circulating the cooling fluid in this region. In addition, theheat treatment system according to this invention suitably selects theintake port, in which the cooling fluid is sucked at a differentposition from a position at which the cooling fluid is sucked by theintake fun, at a position upstream of the filter on the duct, so thatthe heat treatment system can have excellent cooling effects whileinhibiting particles from flying in the carrying-in/out region.

[0081] In the heat treatment system according to the fourth invention,the cooling mechanism may further comprise a second heat exchanger whichis arranged in the duct between the intake port and the filter so as tocool the cooling fluid which is drawn into the duct from the intake fanand the intake port to join.

[0082] According to the heat treatment system of the fourth invention,the filter is arranged downstream of the second heat exchanger in theflow of the cooling fluid, so that the cooling fluid passing through thesecond heat exchanger to be cooled further passes through the filter.Thus, it is possible to inhibit the filter from being damaged by heat.

[0083] According to the fourth invention, there is provided a heattreatment system having a loading chamber in which a mechanism forcarrying an object to be treated in and out of a throat of a bottomportion of a heat treatment furnace and which has a loading chamberseparated as an airtight region, wherein the throat of the bottomportion of the heat treatment furnace is arranged above the loadingchamber, the loading chamber including: a ventilating unit which has aventilating port in the vicinity of the throat and a filter forpurifying and sending a cooling fluid from the ventilating port to thevicinity of the throat from the side; a first heat exchanger which isarranged so as to face the ventilating port in the vicinity of thethroat; an intake fan for sucking the cooling fluid in the vicinity ofthe throat over the first heat exchanger; a circulating duct which formsa circulating path for the cooling fluid between the intake fan and theventilating unit so that the cooling fluid sucked by the intake fanreturns to the ventilating unit, at least a part of sand circulatingduct being arranged below the loading chamber; an intake port which isformed in the part of the circulating duct below the loading chamber sothat a part of the cooling fluid sent by the ventilating unit is suckedbelow the loading chamber; and a second heat exchanger which is arrangedin the circulating duct between the intake port and the filter so thatthe cooling fluid drawn into the circulating duct from the intake fanand the intake port to join is cooled.

[0084] This heat treatment system according to the fourth invention canbe used for purifying and circulating the cooling fluid for cooling thevicinity of the throat, so that this heat treatment system can be usedas a closed type system for blocking the carrying-in/out region forcarrying the objects in and out of the heat treatment furnace fromoutside air and for circulating the cooling fluid in this region. Inaddition, in the heat treatment system according to this invention,above the loading chamber, the flow of the cooling fluid is regulated bythe intake fun and the duct, and the other intake port for the coolingfluid is provided below the loading chamber to similarly regulate theflow of the cooling fluid, so that the heat treatment system can haveexcellent cooling effects while inhibiting particles from flying in thecarrying-in/out region.

BRIEF DESCRIPTION OF THE DRAWINGS

[0085]FIG. 1 is a schematic diagram of a vertical heat treatment systemaccording to the first invention;

[0086]FIG. 2 is an enlarged plan view of a standby box transfer meansshown in FIG. 1;

[0087]FIG. 3 is a top view of the standby box transfer means;

[0088]FIG. 4 is an illustration for explaining the operation of thestandby box transfer means;

[0089]FIG. 5 is a perspective view of a treating-object housing box;

[0090]FIG. 6 is a perspective view showing the state that the lid of thetreating-object housing box is open;

[0091]FIG. 7 is a view showing a locking mechanism for the lid;

[0092]FIG. 8 is an enlarged view showing a principal part of an exampleof a conventional system;

[0093]FIG. 9 is an enlarged view showing a principal part of an exampleof another conventional system;

[0094]FIG. 10 is a perspective view showing an example of a schematicconstruction of a heat treatment system according to the secondinvention;

[0095]FIG. 11 is a plan view of a loading area of the heat treatmentsystem shown in FIG. 10;

[0096]FIG. 12 is an illustration schematically showing an example of aconstruction of a driving means of a wafer transfer mechanism;

[0097]FIG. 13 is an illustration showing the state that the wafertransfer mechanism is positioned at (a) a sheltered motion startingposition and (b) a sheltered position;

[0098]FIG. 14 is an illustration showing the locus of a base when thewafer transfer mechanism takes shelter;

[0099]FIG. 15 is a perspective view showing the whole construction of aheat treatment system according to the third invention;

[0100]FIG. 16 is a partially sectional view of a first holder mountingportion (boat stage) shown in FIG. 15, which is viewed from the top;

[0101]FIG. 17 is a partially sectional view of the first holder mountingportion taken along line A-B of FIG. 15;

[0102]FIG. 18 is a partially sectional view of the first holder mountingportion taken along line C-D of FIG. 15;

[0103]FIG. 19 is a side view of the first holder mounting portion viewedin the direction of arrow E of FIG. 15;

[0104]FIG. 20 is a side view of the first holder mounting portion viewedin the direction of arrow F of FIG. 15;

[0105]FIG. 21 is a conceptual view showing the construction of the firstholder mounting portion;

[0106]FIG. 22 is a schematic diagram showing the first holder mountingportion before a holder is mounted thereon;

[0107]FIG. 23 is schematic diagram showing the first holder mountingportion when the holder is mounted thereon;

[0108]FIG. 24 is a schematic diagram showing the first holder mountingportion when the position of the holder is adjusted;

[0109]FIG. 25 is a schematic diagram showing the first holder mountingportion when it is fixed and when the holder to which wafers aretransferred is mounted thereon;

[0110]FIG. 26 is a schematic diagram showing the first holder mountingportion when the holder is removed;

[0111]FIG. 27 is a schematic diagram showing the first holder mountingportion when the position of a holder mounting table returns;

[0112]FIG. 28 is a flow chart showing the procedure for transferring anobject to be treated, to the holder on the first holder transferringportion;

[0113]FIG. 29 is a perspective view showing a preferred embodiment of avertical heat treatment system according to the fourth invention;

[0114]FIG. 30 is a perspective view showing the vertical heat treatmentsystem of FIG. 29 viewed from a different angle;

[0115]FIG. 31 is a perspective view showing the construction of a gascirculating cooling mechanism of the vertical heat treatment system ofFIG. 29, viewed from the back side of the system body;

[0116]FIG. 32 is a view of the vertical heat treatment system of FIG.29, viewed from the back face;

[0117]FIG. 33 is a view showing a safety mechanism of the vertical heattreatment system of FIG. 29;

[0118]FIG. 34 is a sectional view of top and bottom radiatorsconstituting the gas circulating cooling mechanism of FIG. 31, viewedfrom the side of a surface facing FFU; and

[0119]FIG. 35 is a view schematically showing the flow of nitrogen gasby the gas circulating cooling mechanism of FIG. 31.

BEST MODE FOR CARRYING OUT THE INVENTION

[0120] Referring to the accompanying drawings, a preferred embodiment ofa vertical heat treatment system according to the first invention willbe described below in detail.

[0121]FIG. 1 is a schematic diagram of a vertical heat treatment systemaccording to the first invention, FIG. 2 is an enlarged view of astandby box transfer means shown in FIG. 1, FIG. 3 is a top view of thestandby box transfer means, and FIG. 4 is an illustration for explainingthe operation of the standby box transfer means. Furthermore, the samereference numbers are given to the same components as those of the abovedescribed conventional system.

[0122] First, as shown in FIG. 1, the whole vertical heat treatmentsystem 40 is surrounded by a housing 42 of stainless or the like, andthe interior thereof is divided by a partition wall 26 into two parts ofa housing-box transfer area 44 for transferring a treating-objecthousing box 2 (which will be also hereinafter referred to as a housingbox) and a wafer transfer area 46 serving as a treating-object transferarea for transferring a semiconductor wafer W which is an object to betreated. Clean air flows in the box transfer area 44, and the interiorof the wafer transfer area 46 is in an atmosphere of an inert gas of N₂gas or the like. The treating system 40 mainly comprises: acarrying-in/out port 48 for mainly carrying the housing box 2 in and outof the system 40; a stocker portion 50 for temporarily storing thehousing box 2; a transfer stage 54 for transferring a semiconductorwafer W between the housing box 2 and a treating-object boat 52; atreatment unit 56 for carrying out a predetermined treatment withrespect to the semiconductor wafer W which is transferred to thetreating-object boat 52 to be held thereon; a lid opening/closingmechanism 58 which is provided in the vicinity of the carrying-in/outport 48; an opening/closing mechanism 34 which is provided inside of thewafer transfer area 46 for the transfer stage 54; and a standby boxtransfer means 60 which is a feature of the present invention and whichis provided inside of the housing-box transfer area 44 for the transferstage 54.

[0123] In the above described carrying-in/out port 48, the housing 42 isformed with a box carrying-in/out opening 62 which is always open.Outside of the box carrying-in/out opening 62, there is provided anoutside mounting table 64 for supporting thereon the housing box 2 whichis transferred from the outside. Inside of the box carrying-in/outopening 62, there is provided an inside mounting table 66 for supportingthereon the housing box 2 which slides and moves from the outsidemounting table 64. On the top of the outside or inside mounting table 64or 66, there is provided a sliding plate 68 capable of sliding andmoving between both of the mounting tables 64 and 66. The sliding plate68 is capable of moving while the housing box 2 is supported thereon.Between the inside mounting table 66 and a portion right below the boxcarrying-in/out opening 62 inside of the box carrying-in/out opening 62,the lid opening/closing mechanism 58 capable of vertically moving(rising and setting) is provided for temporarily opening and closing anopening/closing lid 10 of the housing box 2. The reason why theopening/closing lid 10 of the housing box 2 is temporarily taken is thatwafer information, such as the number, positions and states of wafers inthe housing box 2, is intended to be detected by a sensor (not shown).

[0124] On the lid opening/closing mechanism 58, there is mounted a pairof key portions 70 (only one is shown in FIG. 1) which are capable ofprotruding and retracting in horizontal directions and of rotating innormal and reverse directions. By rotating the key portions 70 in normaland reverse directions while the key portions 70 are inserted into keygrooves 16 which are shown in FIGS. 5 through 7, a locking mechanism 12can be locked and unlocked to hold it.

[0125] On the other hand, in the upper portion in the housing-boxtransfer area 44, the above described stocker portion 50 is arranged.The stocker portion 50 is provided with two columns x two stages ofshelves 71 in parallel for temporarily supporting and storing thehousing box 2 thereon in the shown embodiment. Furthermore, the numberof the shelves 71 should not be particularly limited. In fact, a largenumber of shelves are provided.

[0126] Between the two shelves 71, an elevator 72 is provided so as tobe raised. The elevator 72 is provided with a box transfer arm 74 whichextends in horizontal directions and which is capable of swiveling andbending and stretching. Therefore, by causing the box transfer arm 74 tobend and stretch and to move in vertical directions, the housing box 2can be held by the box transfer arm 74 to be transferred between theinside mounting table 66 and the stocker portion 50.

[0127] In the above described transfer stage 54, a single opening 28substantially having the same size as that of the opening 4 (see FIG. 6)of the housing box 2 is formed in the partition wall 26 for separatingboth of the areas 44 and 46 from each other, and a single mounting table30 is horizontally provided on the side of the housing-box transfer area44 of the opening 28, so that the housing box 2 can be mounted thereon.On one side of the mounting table 30, a horizontal actuator 76 forpressingly biasing the housing box 2, which is mounted thereon, towardthe partition wall 26 is provided so that the opening edge of theopening portion 4 of the box vessel 6 substantially airtightly contactsthe opening edge of the opening 28 of the partition wall 26 while theopening/closing lid 10 of the housing box 2 faces the opening 28. Theopening 28 is provided with an opening/closing door 32 for opening andclosing the opening 28. In the housing-box transfer area 44, the standbybox transfer means 60 is provided for causing the housing box 2 to standby in the vicinity of the opening 28. The construction of the transfermeans 60 will be described later.

[0128] Right below the opening 28 inside of the wafer transfer area 46,the opening/closing mechanism 34 is provided for opening and closing theopening/closing lid 10 of the housing box 2 and the opening/closing door32. As this opening/closing mechanism 34, the above describedopening/closing mechanism disclosed in Japanese Patent Laid-Open No.8-279546, or the opening/closing mechanism disclosed in Japanese PatentLaid-Open No. 11-274267 may be used.

[0129] In the wafer transfer area 46, two boat mounting tables 78 (onlyone is shown in FIG. 1) are provided for supporting thereon thetreating-object boat 52 such as a wafer boat. Between the boat mountingtables 78 and the above described transfer stage 54, a wafer transferarm 80 capable of swiveling and bending and stretching is provided. Thiswafer transfer arm 80 is capable of being vertically moved by theelevator 82. Therefore, by causing the wafer transfer arm 80 to stretch,swivel and vertically move, the wafer W can be transferred between thehousing box 2 on the mounting table 30 and the treating-object boat 52on the boat mounting table 78.

[0130] The treating-object boat 52 is made of, e.g., quartz, and capableof supporting, e.g., about 50 to 150 wafers W, on multiple stages at apredetermined pitch.

[0131] Above one side of the wafer transfer area 46, there is arranged atreatment unit 56 comprising a vertical heat treatment furnace having acylindrical treatment vessel 84 of quartz for carrying out apredetermined heat treatment, such as deposition, oxidation ordiffusion, with respect to the large number of wafers W at a time. Belowthe treatment vessel 84, there is arranged a cap 88 capable of beingvertically moved by the elevator 86. By mounting the treating-objectboat 52 on the cap 88 to move the cap 88 upwards, the boat 52 can beloaded in the treatment vessel 84 via the bottom end opening of thetreatment vessel 84. At this time, the bottom end opening of thetreatment vessel 84 is airtightly closed by the cap 88. Between thelowered cap 88 and the above described boat mounting table 87, there isprovided a boat transfer arm 90 capable of bending and stretching andswiveling, so that the treating-object boat 52 can be transferredbetween the boat mounting table 78 and the cap 88.

[0132] On the housing ceiling portion above the above describedtreatment unit 56, there is provided a ceiling ventilating plate havinga ventilating hole, such as a punching metal, for introducing outsideclean area into the treatment unit 56. Above the transfer stage 54 andon the side of the back face of the stocker 50, a ventilating partitionwall 94 having a ventilating hole is provided. On the ventilatingpartition wall 94 on the side of the treatment unit 56, a filter member96 of, e.g., a HEPA filter, and a fan 98 are provided. For example, bypassing clean air (gas) introduced from the outside through the filtermember 96, clean air having a high cleanliness factor is introduced intothe housing-box transfer area 44.

[0133] Also as shown in FIGS. 2 and 3, the standby box transfer means 60which is a feature of the present invention has a lifting table 102engaged with two guide rails 100 which are provided in parallel in theheight direction of the side wall 42A of the housing 42. The liftingtable 102 is capable of being vertically moved by a requiredpredetermined stroke by a lifting means, e.g., a driving ball screw,which passes through the lifting table 102 and which is screwed thereto.Furthermore, the ball screw 104 is capable of being normally andreversely rotated by a driving motor (not shown).

[0134] The lifting table 102 is provided with an arm portion 106 whichextends in horizontal directions and which is capable of bending andswiveling. The arm portion 106 comprises a first arm 106A, the base endportion of which is pivotably mounted on the side of the lifting table102, and a second arm 106B which is pivotably mounted on the tip portionof the first arm 106A. The second arm 106B is set so as to be alwaysdirected in the same direction regardless of the turning angle of thefirst arm 106A. On the tip of the second arm 106B, a box grippingportion 108 is provided. On the bottom portion of the box grippingportion 108, there are provided a pair of claw portions 110 which areslidable in horizontal directions so as to approach or leave each other.The top gripping handle 24 of the housing box 2 can be gripped by theclaw portions 110 to be transferred. Furthermore, the construction ofthe standby box transfer means 60 should not be limited to the abovedescribed construction if it can grip and transfer the housing box 2 asdescribed above.

[0135] The operation of the treatment system 40 with the above describedconstruction will be described below.

[0136] First, the interior of the wafer transfer area 46 is in anatmosphere of an inert gas, e.g., N₂ gas, in order to prevent naturaloxide films from adhering to the surface of the wafers. The interior ofthe housing-box transfer area 44 is maintained in an atmosphere of cleanair. Specifically, clean air is introduced from the ceiling ventilatingplate 92 of the housing 42 into the box transfer area 44 via the filtermember 96 and the ventilating partition wall 94, and circulates in thearea 44 to be exhausted from its bottom.

[0137] First the whole flow of the semiconductor wafers W will bedescribed. The housing box 2 transferred from the outside is mounted onthe outside mounting table 64 so that the opening/closing lid 10 facesthe box carrying-in/out opening 62. Then, by driving the lidopening/closing mechanism 58, the opening/closing lid 10 of the housingbox 2 is temporarily removed, and the number and positions of the wafershoused in the housing box 2 are detected by a sensor (not shown). Ifthis detection is completed, the lid opening/closing mechanism 58 isdriven again, so that the removed opening/closing lid 10 is mounted onthe housing box again.

[0138] Then, if the sliding plate 68 on the outside mounting table 64,on which the housing box 2 is supported, is moved forwards, the slidingplate 68 is transferred to the inside mounting table 66. Then, bydriving the box transfer arm 74, the housing box 2 supported on theinside mounting table 66 is taken to be held. Moreover, by driving theelevator 72, the housing box 2 is transfer to a predetermined positionon the shelf 71 of the stocker portion 50 and temporarily storedthereon. Simultaneously, the housing box 2 which is temporarily storedon the shelf 71 and which houses therein the wafer serving as an objectto be treated is taken by the box transfer arm 74, and the elevator 72is driven to move it downwards as described above. If the mounting table30 of the transfer stage 54 is empty, the housing box 2 is transferredto the mounting table 30 of the transfer stage 54.

[0139] On the other hand, if another housing box 2 has been set on themounting table 30, the housing box 2 on the box transfer arm 74 isgripped by the standby box transfer means, which is a feature of thepresent invention, to be transferred to the vicinity of the opening 28to stand by. The opening/closing lid 10 of the housing box 2 on themounting table 30 is directed to the opening/closing door 32 which isprovided in the partition wall 26, and the housing box 2 is pressinglybiased to be fixed on the mounting table 30 by means of a horizontalactuator which is provided on one side of the mounting table 30.

[0140] By driving the opening/closing mechanism 34 in this state, theopening/closing door 32 of the opening 28 and the opening/closing lid 10of the housing box 2 are removed to take shelter upwards or downwards.Since the peripheral edge portion of the opening portion of the housingbox 2 is pressed against the partition wall 26 to be in a tight contactstate, gases do not flow between both of the areas 44 and 46 via theopening 28. Then, by driving the wafer transfer arm 80 and the elevator82, the wafers W housed in the housing box 2 are taken out, one or aplurality of wafers at a time, to be mounted on the treating-object boat52 which is provided on the boat mounting table 78. If the transfer ofthe wafers W to the treating-object boat 52 is completed, the boattransfer arm 90 is driven, so that the treating-object boat 52 on theboat mounting table 78 is mounted on the cap 88 which has been moved tothe lowermost end. Then, if the transfer of the treating-object boat 52is completed, the elevator 86 is driven to upwardly move the cap 88which has been mounted on the treating-object boat 52, so that the boat52 is introduced into the treatment vessel 84 via the bottom end openingof the treatment vessel 84 of the treatment unit 56 to be loadedtherein. Then, the bottom end opening of the treatment vessel 84 isclosed by the cap 88. In this state, a predetermined heat treatment,e.g., deposition, oxidation or diffusion, is carried out with respect tothe wafers W in the treatment unit 56.

[0141] If the predetermined heat treatment is thus completed, thereverse operation of the above described operation is carried out totake out the treated wafer W. That is, the treating-object boat 52 ismoved downwards from the interior of the treatment vessel 84 to beunloaded to be mounted on the boat mounting table 78. Then, the treatedwafer W is transferred by the wafer transfer arm 80 from the boat 52into the housing box 2. The transfer of the treated wafer W into thehousing box 2 is completed, the opening/closing mechanism 34 is drivento mount the opening/closing lid 10, which has been held by theopening/closing mechanism 34, and the opening/closing door 32 in thehousing box 2 and the opening 28, respectively.

[0142] Then, the box transfer arm 74 is driven to temporarily store thehousing box 2 in the stocker portion 50 or to transfer the housing box 2to the outside of the treatment system 40 via the box carrying-in/outopening 62 without storing the housing box 2. While the box transfer arm74 is transferring the housing box 2 in which the treated wafer ishoused, the standby box transfer means 60 which has gripped an emptyhousing box to stand by is set the empty housing box on the mountingtable 30, and the housing of the treated wafer into the housing box isstarted. Subsequently, the same operation is repeated. Furthermore, theabove described flow of the housing box 2 is only shown as an example.Of course, the invention should not be limited thereto.

[0143] Referring to FIG. 4, the operation of the above described standbybox transfer means 60 will be described below in detail.

[0144] First, in FIG. 4(A), one housing box 2A has been mounted on themounting table 30, and the opening/closing door 32 for closing theopening/closing lid 10 and the opening 28 has been removed by theopening/closing mechanism 34 to be moved downwards. In addition, thesemiconductor wafer W in the housing box 2A has been carried out. Thus,while the wafer in the housing box 2A is being carried out, the boxtransfer arm 74 in the empty state takes the housing box 2B, in which awafer to be treated next is housed, out of the stocker portion 50. Then,as shown in FIG. 2, the standby box transfer means 60 rotates the armportion 106 and drives the box gripping portion 108 to receive thehousing box 2B from the box transfer arm 74 to cause the housing box 2Bto stand by in the vicinity of (in FIG. 4(A), slightly above) thehousing box 2A on the mounting table 30.

[0145] Thus, if the carrying-out of the wafer W in one housing box 2A iscompleted, the opening/closing mechanism 34 is driven to mount theopening/closing lid 10 and the opening/closing door 32. Then, thesliding plate 30A on the mounting table 30 is slightly moved backwardsto interrupt the interference of the housing box 2A with the opening 28,and the emptied housing box 2A is picked up from the top of the mountingtable 30 to be transferred by means of the box transfer arm 74.

[0146] Thus, the top of the mounting table 30 is emptied, the standbybox transfer means 60 is driven to move the arm portion 106 downwards,so that the other housing box 2B which has stood by slightly above themounting table 30 is set on the mounting table 30 as shown in FIG. 4(B).At this time, the pair of claw portions 110 of the box gripping portion108 are caused to slide so as to leave each other, so that the grippinghandle 24 of the housing box 2B can be removed. Then, the housing box 2Bwhich has been newly set on the mounting table 30 is fixed, and thesliding plate 30A is advanced toward the opening 28, so that the tip ofthe housing box 2B contacts the opening 28.

[0147] Then, as shown in FIG. 4(C), both of the opening/closing lid 10of the housing box 2B and the opening/closing door 32 of the opening 28are removed by the opening/closing mechanism 34 as described in FIG.4(A), and the wafer in the housing box 2B is carried out.

[0148] Then, while the wafer is carried out, the housing box 2C in whicha wafer to treated next is housed is transferred above in the samemanner as the above described manner to be caused to stand by therein.Subsequently, the above described operations are similarly repeated.

[0149] On the other hand, when the treated semiconductor wafer isintroduced into an empty housing box, the reverse operation of the abovedescribed operation is carried out. Also in that case, the standby boxtransfer means 60 may be used for causing an empty housing box to standby slightly above the mounting table 30.

[0150] Thus, according to this preferred embodiment, the standby boxtransfer means 60 is used for causing a housing box, in which a wafer tobe treated next is housed, to stand by in the vicinity of the mountingtable 30, or for causing an empty housing box, in which a wafer is to behoused next, to stand by. Therefore, immediately after the operation forcarrying a wafer in and out of the last housing box is completed, theoperation for carrying a wafer in and out of a housing box duringstandby, so that it is possible to rapidly and efficiently carry out thecarrying-in/out operation.

[0151] In addition, the structure of the standby box transfer means 60is relatively simple, and it is sufficient if only one opening/closingmechanism 34 is provided, so that the costs can be smaller than those inconventional systems. In addition, since it is sufficient if only onemounting table 30 is provided, it is possible to greatly reduce theoccupied space.

[0152] While the housing box 2 has been caused to stand by slightlyabove the mounting table 30, this standby position should notparticularly be limited if it is in the vicinity of the mounting table30. For example, the housing box may be caused to stand by in asubstantially lateral direction of the mounting table 30.

[0153] While the semiconductor wafer has been described as an example ofan object to be treated, the present invention should not be limitedthereto, but the invention may be applied to a glass substrate or an LCDsubstrate.

[0154] As described above, according to the vertical heat treatmentsystem of the first invention, excellent effects can be provided asfollows.

[0155] According to the first invention, when an object to be treated iscarried out of one treating-object housing box to be carried in thetreating-object transfer area via the opening of the partition wall, thestandby box transfer means is used for causing the nest treating-objecthousing box to stand by in the vicinity of the opening (mounting table).Then, when the carrying-out of the object in the last treating-objecthousing box is completed, the treating-object housing box during standbycan be immediately set in the above described opening to carry theobject out. Therefore, the carrying and transfer of the object in and tothe treating-object transfer area can be quickly and efficiently carriedout in a space saving state without causing the structure to be socomplicated.

[0156] Also when the treated object is transferred, the carrying-in/outof the object can be quickly and efficiently carried out in the samemanner as the above described manner by causing an empty treating-objecthousing box to stand by in the vicinity of the mounting table.

[0157] Referring to the accompanying drawings, the second invention willbe described below in detail.

[0158]FIG. 10 is a perspective view showing an example of a schematicconstruction of a vertical heat treatment system according to the secondpreferred embodiment, and FIG. 11 is a plan view of a loading area ofthe vertical heat treatment system shown in FIG. 10.

[0159] This heat treatment system 1010 is separated into front and rearportions by a partition wall 1012, and has a housing 1011 which forms acarrier transfer area Sa in which a carrier (cassette) housing therein asemiconductor wafer serving as an object to be treated is carried in andout and stored, and a loading area Sb in which the semiconductor waferis transferred and heat-treated. In the front face of the housing 1011,a carrying-in/out opening 1013 for carrying a carrier 1020 in and out isformed, and a carrying-in/out stage 1014 serving as an inlet/outlet portto the carrying-in/out opening 1013 is provided. The carrier transferarea Sa is maintained in an atmosphere of atmospheric air, and theloading area Sb is maintained in an atmosphere of atmospheric air or anatmosphere of an inert gas, such as nitrogen gas. In FIG. 10, referencenumber 1015 denotes a sensor mechanism for opening a lid 1020A of thecarrier 1020 to detect the position and number of semiconductor wafers,reference number 1016 denotes a shelf-like carrier storage portion forstoring a plurality of carriers 1020, and reference number 1017 denotesa notch aligning mechanism for aligning notches (cut-out portions),which are formed in the peripheral edge portions of the semiconductorwafers, in one direction in order to arrange crystal orientation.

[0160] The carrier 1020 comprises a plastic vessel capable of housingtherein a plurality of, e.g., about 13 to 25, semiconductor wafershaving a predetermined diameter, e.g., a diameter of 300 mm, on multiplestages in a horizontal state at regular intervals in verticaldirections. The carrier 1020 is detachably provided with a lid 1020A forairtightly closing a wafer outlet (not shown) which is formed in theback face thereof.

[0161] In the carrier transfer area Sa, carrier mounting portions 1021are provided in the vicinity of the partition wall 1012 for supportingthereon the carrier 1020. In order to improve throughput, the pluralityof, e.g., two, carrier mounting portions 1021 are provided so as to bearranged in vertical directions although only one carrier mountingportion is shown for convenience. Thus, while the semiconductor wafersare being transferred in one carrier mounting portion, the carrier 1020can be exchanged in the other carrier mounting portion.

[0162] In the carrier transfer area Sa, there is provided a carriertransfer mechanism 1025 for transferring the carrier 1020 between thecarrier storage portions 1016, 1016 and the carrier mounting portion1021.

[0163] The carrier transfer mechanism 1025 comprises: a lifting guide1025A which is provided on one side of the housing 1011; a lifting arm1025B which is vertically moved by the lifting guide 1025A; and atransfer arm 1025C which is provided on the lifting arm 1025B so as tobe rotatable on the horizontal plane. As shown in FIG. 11, the transferarm 1026C comprises a first arm 1251, and a second arm 1252 which isprovided on the tip portion of the first arm 1251 so as to be rotatableon the horizontal plane.

[0164] The partition wall 1012 has an opening portion 1022, which isarranged so as to correspond to the height of each of the carriermounting portions 1021, for establishing a communication between thecarrier transfer area Sa and the loading area Sb. The opening portion1022 substantially has the same diameter as that of the wafer outlet ofthe carrier 1020.

[0165] The partition wall 1012 is provided with a door (1023 in FIG. 11)for closing the opening portion 1022 from the side of the loading areaSb. This door 1023 is open and closed by a door opening/closingmechanism (not shown) which is provided in the loading area Sb.

[0166] There is provided a lid opening/closing mechanism (not shown) foropening and closing the lid 1020A of the carrier 1020. By thismechanism, the door 1020A and the lid 1020A of the carrier 1020 aremoved to the loading area Sb and caused to take shelter upwards ordownwards so as not to prevent the semiconductor wafers from beingtransferred.

[0167] In the rear portion (lower portion in FIG. 11) of the loadingarea Sb, a heat treatment furnace 1028 is provided in the upper portion,and a boat elevator mechanism 1030 serving as a lifting mechanism whichis moved in vertical directions for carrying wafer boats 1031A and 1031Bof, e.g., quartz, each of which is a holder for holding a plurality of,e.g., about 50 to 150, semiconductor wafers on multiple stages atregular intervals in vertical directions, in and out of the heattreatment furnace 1028 is provided so as to face the carrier mountingportion 1021.

[0168] The boat elevator mechanism 1030 comprises a lifting guide 1032A,and a mounting table 1032B on which the wafer boats 1031A and 1031B aresupported and which is vertically moved by the lifting guide 1032A. Themounting table 1032B, together with the wafer boats 1031A and 1031B, isintroduced into the heat treatment furnace 1028 to serve as a lid forclosing a bottom end opening 1028A of the heat treatment furnace 1028.

[0169] In the vicinity of the bottom end opening 1028A of the heattreatment furnace 1028, there is provided a shutter 1033 for closing thebottom end opening 1028A when the wafer boat after heat treatment iscarried out of the heat treatment furnace 1028. The shutter 1033 isdesigned to be rotated by a shutter driving mechanism about a verticallyextending shaft to be open and closed.

[0170] On one side portion of the housing 1011 in the loading area Sb,there is provided a boat mounting portion 1035 serving as a holdermounting portion on which the wafer boats 1031A and 1031B are supportedfor transferring the semiconductor wafers. The boat mounting portion1035 has first and second mounting portions 1035A and 1035B which arearranged in longitudinal directions.

[0171] In the loading area Sb, there is provided a boat transfermechanism 1036 which is a holder transfer mechanism for transferring thewafer boats 1031A and 1031B between the first mounting portion 1035A orsecond mounting portion 1035 of the boat mounting portion 1035 and themounting table 1032B of the boat elevator mechanism 1030 and between thefirst mounting portion 1035A and the second mounting portion 1035B.

[0172] The boat transfer mechanism 1036 comprises a first arm 1036Awhich is rotatable on the horizontal plane and which is movable invertical directions, and a supporting arm 1036B which is provided on thetip portion of the first arm 1036A so as to be rotatable on thehorizontal plane and which has a substantially C-shaped opening 1036Ccapable of vertically supporting the wafer boats 1031A and 1031B.

[0173] The supporting arm 1036B is arranged so that the locus of thecenter of the opening 1036C when being driven includes the rotationcenter of the first arm 1036A. By rotating the first arm 1036A and thesupporting arm 1036B in synchronism with each other, the wafer boats1031A and 1031B are transferred on the horizontal plane.

[0174] At a level above the lowest position of the boat transfermechanism 1036, there is provided a wafer transfer mechanism 1040 whichhas a motion space region overlapping with the motion space region ofthe boat transfer mechanism 1036 and which is a treating-object transfermechanism for transferring the semiconductor wafers between the carrier1020 on the carrier mounting portion 1021 and the wafer boat 1031B onthe boat mounting portion 1035.

[0175] As shown in FIG. 11, the wafer transfer mechanism 1040 comprises:a lifting guide 1041 which is provided on the opposite side face to theboat mounting portion 1035 via a part of the motion space region of theboat transfer mechanism 1036; a swivel arm 1042 which is movable invertical directions by means of the lifting guide 1041 and which isrotatable about a vertically extending shaft 1421; an elongatedrectangular transfer head 1043 which is provided on the tip portion ofthe swivel arm 1042 so as to be rotatable on the horizontal plane; and asupporting arm 1044 which comprises one or a plurality of, e.g., one tofive, fork-shaped thin plates and which is provided on the transfer head1043 so as to be retractable in their longitudinal directions.

[0176] Means for driving the wafer transfer mechanism 1040 comprises astretching mechanism 1045 for rotating the swivel arm 1042, and a belttransmission mechanism for transmitting the rotational motion of theswivel arm 1042 to the transfer head 1043.

[0177] For example, the stretching mechanism 1045 comprises an aircylinder. One end of the stretching mechanism 1045 is rotatablyconnected to a rotation center shaft 1451 which is different from therotation center shaft 1421 of the swivel arm 1042, and the other end isrotatably connected to a connecting portion (1056 in FIG. 12) in the tipside portion of the swivel arm 1042. The stretching direction of thestretching mechanism 1045 obliquely traverses the longitudinal directionof the swivel arm 1042.

[0178] The stretching mechanism 1045 is adjusted so that the wholelength thereof expands and contracts in the range of, e.g., from 195 to250 mm. Thus, the motion space region of the wafer transfer mechanism1040 is set to be in a predetermined range, and the direction or angularstate of the swivel arm 1042 can be surely controlled.

[0179] For example, as shown in FIG. 12, the belt transmission mechanismserving as the means for driving the transfer head 1043 comprises belttransmission mechanisms 1051A and 1051B wherein belts 1054A and 1054Bare tensionally extended between and wound onto pulleys and which arecombined with each other in two stages. Specifically, the center shaft1511 of a fixed pulley 1052A of one belt transmission mechanism 1051A isarranged while being fixed to the rotation center shaft 1421 of theswivel arm 1042, and the rotation center shaft 1512 of a driven pulley1053B of the other belt transmission mechanism 1051B is fixed to therotation center shaft 1431 of the transfer head 1043. In addition, thedriven pulley 1053A of the one belt transmission mechanism 1051A and thedriving pulley 1052B of the other belt transmission mechanism 1051B arefixed to each other so that the their rotation center shafts arecoincident with each other. In the figure, reference number 1055 denotesa tension pulley for increasing the winding angle of the driven pulley1053B and driving pulley 1052B of the other belt transmission mechanism1051B.

[0180] The driven pulley 1053A of the one belt transmission system 1051Ahas a smaller diameter than that of the fixed pulley 1052A, and thepulley ratio of the fixed pulley 1052A to the driven pulley 1053A is setto be, e.g., 42:24.

[0181] The pulley ratio of the driving pulley 1052B to the driven pulley1053B in the other belt transmission system is set to be, e.g., 1:1.

[0182] According to this driving means, the swivel arm 1042 is rotatedabout the rotation center shaft 1421 on its one end by the expansion andcontraction of the stretching mechanism 1045, so that the driven pulley1053A of the one belt transmission system 1051A is rotated in theopposite direction to the rotational direction of the swivel arm 1042.In accordance therewith, the driving pulley 1052B of the other belttransmission system 1051B is rotated, and the driven pulley 1053B of theother belt transmission system 1051B is rotated via the belt 1054B. As aresult, the transfer head 1043 is rotated by a rotational angleaccording to the rotational angle of the swivel arm.

[0183] The operation of the above described vertical heat treatmentsystem 1010 will be described below.

[0184] First, if the carrier 1020 is mounted on the carrying-in/outstage 1014 from the outside by an automatic transfer robot (not shown)or an operator, the carrier 1020 is carried in via the carrying-in/outopening 1013, and the sensor mechanism 1015 opens the lid of the carrier1020 to detect the positions and number of semiconductor wafers in thecarrier 1020. Thereafter, while the lid 1020A of the carrier 1020 isclosed, the carrier 1020 is transferred to the notch aligning mechanismby means of the carrier transfer mechanism 1025, and transferred to thecarrier mounting portion 1021 after notches (cut-out portions), whichare formed in the peripheral edge portions of the semiconductor wafers,are aligned in one direction. In addition, in accordance with theprogression of the heat treatment, the carrier 1020 is stored in thecarrier storage portion 1016 once, and thereafter, transferred to thecarrier mounting portion 1021.

[0185] If the lid 1020A of the carrier 1020 on the carrier mountingportion 1021 and the door 1023 of the opening 1022 of the partition wall1012 are open, the semiconductor wafers are taken out of the carrier1020 to be sequentially transferred to the wafer boat 1031B, whichstands by on the first mounting portion 1035A of the boat mountingportion 1035, by means of the wafer transfer mechanism 1040,specifically by carrying out the rotation of the swivel arm 1042, therotation of the transfer head 1043 and the expansion and contraction ofthe supporting arm 1044 in a controlled state. Meanwhile, the boattransfer mechanism 1036 is moved downwards to the lower position to takeshelter, so that the wafer transfer mechanism 1040 does not interferewith the boat transfer mechanism 1036.

[0186] If the transfer of the semiconductor wafers from the carrier 1020on the carrier mounting portion 1021 to the wafer boat 1031B on thefirst mounting portion 1035A is completed, the wafer transfer mechanism1040 is transferred from its motion space region to a sheltered positionon the other side face of the housing 1011.

[0187] Specifically, if the stretching mechanism 1045 is contracted asshown in FIG. 13(b) after the wafer transfer mechanism 1040 is moved toa specific reference position in its motion space region as shown inFIG. 13(a), the swivel arm 1042 is rotated about its rotation centershaft 1421, and simultaneously, the transfer head 1043 is rotated by thebelt transmission mechanism, which is means for driving the transferhead 1043, by a rotational angle corresponding to the rotational angleof the swivel arm 1042 to be transferred to a predetermined shelteredposition. That is, as shown in FIG. 14, while the transfer head 1043 inthe wafer transfer mechanism 1040 is rotated (revolved) clockwise aroundthe rotation center shaft 1421 of the swivel arm 1042, the transfer head1043 itself is rotated (rotated on its axis) in the reverse direction ofthe direction of rotation of the swivel arm 1042 (counterclockwise) tobe moved on the horizontal plane along the outer peripheral edge of themounting table 1032B in the boat elevator mechanism 1030.

[0188] The reference position of the wafer transfer mechanism 1040 inthe motion space region is previously set in accordance with, e.g., thepulley ratio of one belt transmission system 1051A in the means fordriving the transfer head 1043. Thus, the above described shelteredmotion is surely carried out, and the wafer transfer mechanism 1040 istransferred to a predetermined sheltered position.

[0189] In this state, the wafer boat holding the semiconductor wafers onthe first transfer portion 1035A of the boat transfer portion 1035 istransferred to the mounting table 1032B in the boat elevator mechanism1030 by means of the boat transfer mechanism 1036, and then, the waferboat, together with the mounting table 1032B, is introduced into theheat treatment furnace 1028 by means of the boat elevator mechanism1030. Then, the boat transfer mechanism 1036 is moved to a shelteredposition below its motion space region, and one wafer boat isheat-treated. Simultaneously, the transfer of the semiconductor wafersfor the wafer boat on the first transfer portion 1035A is carried out inparallel.

[0190] After the heat treatment is completed, the mounting table 1032Bis moved downwards to cause the wafer boat after the heat treatment tobe carried out of the heat treatment furnace 1028 into the loading areaSb, and the bottom end opening 1028A of the heat treatment furnace 1028is immediately closed by the shutter 1033.

[0191] If the wafer boat after the heat treatment is carried out, thewafer boat 1031B before the heat treatment, which stands by on the firstmounting portion 1035A, is first transferred to the second mountingportion 1035B by means of the boat transfer mechanism 1036. Then, thewafer boat 1031A after the heat treatment is transferred from themounting table 1032B to the first mounting portion 1035A, and finally,the wafer boat 1031B on the second mounting portion 1035B is transferredto the mounting table 1032B.

[0192] Then, the semiconductor wafers are taken out of the wafer boat1031A by means of the wafer transfer mechanism 1040 after the heattreatment, to be loaded in the carrier 1020 on the carrier mountingportion 1021 to be transferred by means of the carrier transfermechanism 1025 to be carried out via the carrying-in/out opening 1013.

[0193] According to the above described heat treatment system 1010, thewafer transfer mechanism 1040 is moved on the horizontal plane, notabove the boat transfer mechanism 1036, to take shelter on the side faceof the housing 1011, so that the wafer boat during the transfer does notinterfere with the wafer transfer mechanism 1040. In addition, since thewafer transfer mechanism 1040 at the lower position takes shelter on thesame plane as that of the elevator mechanism, the influence of heat fromthe heat treatment furnace can be very small, so that the heat treatmentsystem can be stably operated for a long term.

[0194] When the wafer transfer mechanism 1040 is moved from the motionspace region to the sheltered position, the transfer head 1043 of thewafer transfer mechanism 1040 is moved on the horizontal plane along theouter peripheral edge of the mounting table 1032B of the boat elevatormechanism 1030 at the lowest position, i.e., through an arc-shapedpassage which is curved in the opposite direction to the locus L of therotation center shaft 1431 of the transfer head 1043. Therefore, thespace required for the sheltered motion of the wafer transfer mechanism1040 can be reduced. In addition, in the loading area Sb, the boatmounting portion 1035 and the boat elevator mechanism 1030 can bearranged at a high spatial utilization factor. For example, the distancebetween the carrier mounting portion 1021 and the boat elevatormechanism 1030 can be smaller than the conventional distance by about 20to 30%. Therefore, it is possible to miniaturize the whole system whilemaintaining a high throughput.

[0195] An example of dimensions in the above described vertical heattreatment system 1010 will be described below. At the reference position(sheltered motion starting position) in the motion space region for thewafer transfer mechanism 1040, the rotational angle α of the swivel arm1042 with respect to the side wall face of the housing 1011 is 64.5°,the rotational angle β of the transfer head 1043 with respect to thecenter shaft of the swivel arm 1042 in longitudinal directions is 39.5°,the overall length of the stretching mechanism 1045 is 247.6 mm (seeFIG. 13(a)), and the overall length of the stretching mechanism 1045 is198.5 mm when the wafer transfer mechanism 1040 is positioned at itssheltered position.

[0196] While the preferred embodiment of the present invention has beendescribed above, the operation of the present invention should not belimited to the above described operation. For example, the object to betreated may be transferred from the carrier on the carrier mountingportion directly to the wafer boat on the mounting table in the boatelevator mechanism. This is particularly useful when a small number ofvarious objects to be treated are treated.

[0197] While the heat treatment in one wafer boat is carried out, whenthe transfer of the semiconductor wafers with respect to the other waferboat on the first transfer portion is completed, the transfer of thewafer boat from the first mounting portion to the second mountingportion may be previously carried out by means of the boat transfermechanism.

[0198] In the transfer head driving means, the driven pulley of onetransmission mechanism rotated by the rotation of the swivel arm may beintegrally formed with the driven pulley of the other belt transmissionmechanism to which the transfer head is connected.

[0199] The objects treated in the vertical heat treatment systemaccording to the present invention should not be limited tosemiconductor wafers. For example, the vertical heat treatment systemaccording to the present invention is suitably used for heat-treatingglass wafers or ceramic wafers.

[0200] According to the vertical heat treatment system of the secondinvention, the treating-object transfer mechanism is caused to takeshelter on one side face of the housing when the holder is transferred.Therefore, the holder does not interfere with the treating-objecttransfer mechanism during the transfer of the holder. In addition, sincethe lifting mechanism takes shelter on the same plane when the liftingmechanism is positioned at its lower position, the influence of heatfrom the heat treatment furnace or the like can be very small, and thesystem can be stably operated for a long term.

[0201] In addition, since the transfer head of the treating-objecttransfer mechanism is moved along the outer peripheral edge of theholder supporting face of the lifting mechanism, the holder mountingportions and so forth can be arranged in the loading area while thespace required for the sheltered motion is very small. Therefore, it ispossible to miniaturize the whole system while maintaining the highthroughput.

[0202] According to the method for controlling the vertical heattreatment system according to the second invention, it is possible tosurely prevent the holder from interfering with the treating-objecttransfer mechanism during the transfer of the holder, and the influenceof heat from the heat treatment furnace and so forth can be very small,so that it is possible to stably operate the vertical heat treatmentsystem.

[0203] Moreover, since the transfer head of the treating-object transfermechanism can be caused to take shelter in a relatively small space, theholder mounting portion and so forth can be arranged at a high spatialutilization factor, so that it is possible to miniaturize the wholesystem while maintaining the high throughput.

[0204] Referring to the accompanying drawings, the third invention willbe described below in detail.

[0205] [First Preferred Embodiment]

[0206] (Schematic Construction of Whole Heat Treatment System)

[0207] Referring to the accompanying drawings, the preferred embodimentof the third invention will be described below in detail.

[0208]FIG. 15 is a schematic perspective view of a vertical heattreatment system according to the third invention.

[0209] As shown in FIG. 15, a housing 2010 defining the contour of avertical heat treatment system is separated by a partition wall 2012into a carrier transfer area Sa and a loading area Sb.

[0210] In the carrier transfer area Sa, the carrying-in/out, storage andso forth of a carrier, in which semiconductor wafers W (which will behereinafter referred to as wafers W) serving as objects to be treated(which will be also hereinafter referred as substrates to be treated)have been housed, are carried out. In the loading area Sb, the transferof the wafers W from the interior of the carrier 2014 to a holder (whichwill be also hereinafter referred to as a boat) 2016, and the carryingof the holder 2016 in and out of a heat treatment furnace 2018, and soforth are carried out.

[0211] Clean air is supplied to the carrier transfer area Sa via afilter (not shown), so that the carrier transfer area Sa is maintainedin an atmosphere of atmospheric air. Clean air or an inert gas, e.g.,nitrogen gas, is supplied to the loading area Sb, so that the loadingarea Sb is maintained in an atmosphere of atmospheric air or anatmosphere of the inert gas.

[0212] The carrier 2014 is a so-called closed type carrier, which housestherein a plurality of wafers W and which is closed by an FIMS(Front-opening Interface Mechanical Standard) door 2015. Specifically,the carrier 2014 is a portable plastic vessel capable of housing thereina plurality of, e.g., about 13 to 25, semiconductor wafers having apredetermined diameter, e.g., a diameter of 300 mm, in a horizontalstate on multiple stages at regular intervals in vertical directions,and the FIMS door 2015 is detachably provided for airtightly closing awafer outlet which is formed in the front face of the vessel.

[0213] The front face portion of the housing 2010 is provided with acarrier carrying-in/out opening 2020 for carrying the carrier 2014 inand out by means of an operator or a transfer robot. The carriercarrying-in/out opening 2020 is provided with a load port 2022 forcarrying the carrier 2014 in or out of the carrier transfer area Sa. Bymeans of a transfer mechanism 2024 provided on the load port 2022, thecarrier 2014 is moved on the load port 2022 to be transferred to theinterior of the carrier transfer area Sa.

[0214] In the carrier transfer area Sa, shelf-like storage portions 2026for storing a plurality of carriers 2014 are provided above the loadport 2022 and above the side of the partition wall 2012.

[0215] On the side of the partition wall 2012 in the carrier transferarea Sa, a carrier mounting portion (which will be also hereinafterreferred to as an FIMS port) 2027 is provided for supporting thereon thecarrier 2014 to transfer the wafers. In the carrier transfer area Sa, acarrier transfer mechanism 2028 is provided for transferring the carrier2014 between the load port 2022, the storage portion 2026 and thecarrier mounting portion 2027.

[0216] The carrier transfer mechanism 2028 comprises: a lifting arm 2028b which is vertically moved by a lifting mechanism 2028 a provided onone side portion of the carrier transfer area Sa; an arm 2028 c which isprovided on the lifting arm 2028 b; and a transfer arm 2028 d which isprovided on the arm 2028 c for supporting thereon the bottom of thecarrier 2014 to transfer the carrier 2014.

[0217] The partition wall 2012 is provided with a door 2030 which isformed so as to have a shape corresponding to the wafer outlet of thecarrier 2014 and which is capable of being open and closed. By openingthe door 2030 while the carrier 2014 contacts the door 2030, the wafersW in the carrier 2014 can be taken in and out of the loading area Sb.

[0218] On the other hand, above the inside of the loading area Sb, a lid2032 is provided so as to be capable of being vertically moved by alifting mechanism (which will be also hereinafter referred to as a boatelevator) 2034. The lid 2032 can support thereon the holder 2016 of,e.g., quartz, which holds a plurality of, e.g., about 100 to 150, wafersW on multiple stages at regular intervals in vertical directions. Byvertically moving the lid 2032 by means of the lifting mechanism 2024,the holder 2016 holding the wafers w can be carried in and out of theheat treatment chamber of the heat treatment furnace 2018. In thevicinity of the throat of the heat treatment furnace 2018, there isprovided a shutter 2026 which is capable of being open and closed inhorizontal directions for closing the throat when the lid 2032 is moveddownwards and when the holder 2016 is carried out after the heattreatment.

[0219] In one side portion of the loading area Sb, a first holdermounting portion (which will be also hereinafter referred to as aholding supporting mechanism or a boat stage) 2028 is provided forsupporting thereon the holder 2016 in order to transfer the wafers W.Behind the first holder mounting portion 2038, a second holder mountingportion (which will be also hereinafter referred to as a standby stage)2040 is provided for supporting thereon the holder 2016 which holds thewafers W serving as the objects to be treated.

[0220] Between the carrier transfer portion 2027 and the heat treatmentfurnace 2018 in the lower portion in the loading area Sb, a holdertransfer mechanism 2042 is provided for transferring the holder 2016between the first holder mounting portion 2023, the second holdermounting portion 2040 and the lid 2017.

[0221] The holder transfer mechanism 2042 comprises a first arm 2042 acapable of being rotated in horizontal directions and moved in verticaldirections, and a supporting arm 2042 b which is supported on the tipportion of the first arm 2014 a so as to be rotatable in horizontaldirections and which is capable of supporting the holder 2016 invertical directions, the supporting arm 2042 b having a substantiallyC-shaped opening.

[0222] Above the holder transfer mechanism 2042, a transfer mechanism2044 is provided for transferring the wafers W between the carrier 2014on the carrier transfer portion 2027 and the holder 2016 on the firstholder mounting portion 2038. The transfer mechanism 2044 comprises alifting mechanism 2044 a, a first arm 2044 b which is connected to thelifting mechanism 2044 a and which is rotatable in horizontaldirections, a second arm 2044 c which is connected to the first arm 2044b and which is rotatable in horizontal directions, and a supporting arm2044 d which is provided on the second arm 2044 c and which isretractable. The supporting arm 2044 d comprises a plurality of, e.g.,two to five, fork-shaped thin plates, and is movable while supportingthereon the wafers W.

[0223] The procedure for heat-treating wafers W in the vertical heattreatment system with this construction will be described below.

[0224] After the carrier 2014 is supported on the load port 2022, thetransfer mechanism 2024 transfers the carrier 2014 to the carriertransfer area Sa via the carrier carrying-in/out opening 2020. Then, thecarrier 2014 on the load port 2022 in the carrier transfer area Sa istransferred to the storage portion 2026 by means of the carrier transfermechanism 2028. Moreover, the carrier 2014 in the storage portion 2026is transferred to the carrier mounting portion 2027 by means of thecarrier transfer mechanism 2028.

[0225] If the FIMS door 2015 of the carrier 2014 on the carrier mountingportion 2027 and the door 2030 of the partition wall 2012 are open, thetransfer mechanism 2044 takes the semiconductor wafers W out of thecarrier 2014 to sequentially transfer the wafers W to an empty holder2016 which stands by on the first holder mounting portion 2038.

[0226] By the holder transfer mechanism 2024, the holder 2016 holdingthe wafers W is transferred to the top face of the lid 2032 from thefirst holder mounting portion 2038, via the second holder mountingportion 2040 if necessary. The holder 2016 on the lid 2032 holding thewafers W are housed in the heat treatment chamber of the heat treatmentfurnace 2018 by means of the lifting mechanism 2034, and a heattreatment is carried out therein. Furthermore, when the lid 2032 movesin vertical directions, the shutter 2036 is caused to take shelter.

[0227] After the heat treatment is completed, the lid 2032 is moveddownwards by means of the lifting mechanism 2034, and the holder 2016 iscarried out of the heat treatment chamber of the heat treatment furnace2018 to be transferred to the loading area Sb. The holder 2016 which iscarried out of the heat treatment chamber of the heat treatment furnace2018 and which holds the heat-treated wafers W is transferred from thetop face of the lid 2032 to the top face of the first holder mountingportion 2038. The wafers W are moved from the holder 2016, which isarranged on the first holder mounting portion 2038, to the carrier 2014,which is arranged on the carrier mounting portion 2017, by means of thetransfer mechanism 2044.

[0228] The carrier 2014 housing therein the heat-treated wafers W ismounted on the load port 2022 by means of the carrier transfer mechanism2028, and is carried out of the carrier carrying-in/out opening 2020 bymeans of the transfer mechanism 2024.

[0229] (Details of First Holder Mounting Portion)

[0230] The first holder mounting portion (boat stage) 2038 will bedescribed below in detail. FIG. 16 is a partially sectional view of thefirst holder mounting portion 2038 viewed from the top. FIGS. 17 and 18are partially sectional views of the first holder mounting portion 2038taken along lines A-B and C-D of FIG. 15, respectively. FIGS. 19 and 20are side views of the first holder mounting portion 2038 viewed in thedirections of arrows E and F of FIG. 15, respectively.

[0231] In FIGS. 17 and 18, a holder bottom plate 2160 of the holder 2016is shown by a two-dot chain line. The holder bottom plate 2160 has aflat ring shape having a circular outer periphery 2162, a part of whichis cut by a straight line, and a substantially circular opening portion(inner periphery) 2164 which is concentric with the outer periphery2162. The opening portion 2164 has a pair of cut-outs 166 a and 166 b inthe vicinity of both ends in radial directions. Each of the cut-outs 166a and 166 b has a substantially isosceles triangular shape which issymmetrical with respect to the center of the opening portion 2164, andthe vertex thereof is rounded.

[0232] The first holder mounting portion 2038 comprises a holdermounting table 2050 for mainly supporting thereon the holder 2016, abase 2056 fixed to the heat treatment system, and a ball retainer 2062for retaining a spherical ball 2060 which is arranged between the holdermounting table 2050 and the base 2056. On the holder mounting table2050, a pair of substantially cylindrical protruding portions 2068 a and2068 b are arranged for positioning the holder 2016. The holder mountingtable 2050 comprises a disk-shaped holder mounting table body 2050 a,and a narrow flat ring-shaped top rail portion 2050 b which issubstantially concentric with the holder mounting table body 2050 a andwhich has an outer periphery having a slightly smaller diameter thanthat of the holder mounting table body 2050 a.

[0233] The holder mounting table body 2050 a is formed with a circuitopening portion 2052 which is substantially concentric with the holdermounting table body 2050 a, and a pair of circular opening portions 2054a and 2054 b which correspond to the protruding portions 2068 a and 2068b and which are symmetrical with each other with respect to the centerof the holder mounting table body 2050 a.

[0234] The base 2056 comprises a flat ring-shaped base top plate 2056 awhich substantially corresponds to the holder mounting table body 2050a, a flat ring-shaped bottom rail portion 2056 b which is arranged onthe top face of the base top plate 2056 a and which substantiallycorresponds to the top rail portion 2050 b, a substantially cylindricalconnecting portion 2056 c which is connected to the lower portion of thebase top plate 2056 a, and a flat ring-shaped base bottom plate 2056 dwhich is connected to the connecting portion 2056 c. The base top plate2056 a is formed with a pair of substantially circular opening portions2058 a and 2058 b, the positions and shapes of which correspond to thoseof the opening portions 2054 a and 2054 b of the holder mounting table2050, respectively.

[0235] The base top plate 2056 a is formed with a pair of substantiallyrectangular opening portions 2057 a and 2057 b on its outer periphery onboth ends in radial directions. Furthermore, the ball retainer 2062 andthe bottom rail portion 2056 b are formed continuously even in theopening portions 2057 a and 2057 b.

[0236] The ball retainer 2062 has a flat ring shape which substantiallycorresponds to the top rail portion 2050 b and the bottom rail portion2056 b. The thickness of the ball retainer 2062 is smaller than thediameter of the ball 2060. The ball retainer 20623 is formed with acircular opening portion which has a slightly greater diameter than thediameter of the ball 2060, and the ball 2060 is retained in this openingportion.

[0237] The ball 2060 retained in the ball retainer 2062 rotates betweenthe top rail portion 2050 b and the bottom rail portion 2056 b.Therefore, friction during sliding motion between the top rail portion2050 b and the bottom rail portion 2056 b is reduced by the ball 2060.

[0238] That is, according to the third invention, the combination of theball 2060 with the ball retainer 2062 for retaining the same functionsas a sliding mechanism for facilitating motion along the principal planeof the holder mounting table 2050 (the top or bottom face of the holdermounting table body 2050 a) between the holder mounting table 2050 andthe base 2056. Furthermore, this motion may include rotational motionabout an axis perpendicular to the principal part of the holder mountingtable 2050.

[0239] The protruding portions 2068 a and 2068 b are connected to shafts2066 a and 2066 b, respectively, which are connected to air cylinders2068 a and 2068 b, respectively, which are provided on the base bottomplate 2056 d. The shafts 2066 a and 2066 b have an L shape, and passthrough the opening portions 2058 a and 2058 b of the base 2056 and theopening portions 2054 a and 2054 b of the holder mounting table 2050,respectively.

[0240] Air or nitrogen gas is supplied to each of the air cylinders 2064a and 2064 b (gas piping is not shown), so that the shafts 2066 a and2066 b can be pushed out or pulled back toward the center of the base2056 by their gas pressures, respectively. If the shafts 2066 a and 2066b are pushed out or pulled back, the protruding portions 2068 a and 2068b move so as to approach or leave the center of the base 2056,respectively.

[0241] In FIGS. 16 and 17, the solid line shows the state that the gaspressures in the air cylinders 2064 a and 2064 b are reduced to pullboth of the shafts 2066 a and 2066 b back.

[0242] By the operation of the air cylinders 2064 a and 2064 b, thedistance between the centers of the protruding portions 2068 a and 2068b varies between the maximum value L2 and the minimum value L1.Furthermore, at this time, the relationship between the stroke ΔL of theair cylinders 2064 a, 2064 b and the maximum value L2 and minimum valueL1 of the distance between the protruding portions 2068 a and 2068 b isL2=L1+2ΔL.

[0243] If the distance between the protruding portions 2068 a and 2068 bis increased, the protruding portions 2068 a and 2068 b enter (engage)the cut-outs 166 a and 166 b, which are provided in the holder bottomplate 2160, respectively, to stop in the vicinity of the vertexes of thecut-outs 166 a and 166 b, respectively.

[0244] At this time, if the holder 2016 is positioned at a predeterminedposition and in a predetermined direction on the base 2056 (at thecenter of the base 2056 and in a direction in which the cut-outs 166 aand 166 b correspond to the protruding portions 2068 a and 2068 b), therelationship between the positions and directions of the holder 2016 andthe base 2056 is maintained.

[0245] On the other hand, if the arrangement of the holder 2016 isshifted from this predetermined arrangement, the holder 2016 moves inaccordance with the movement of the protruding portions 2068 a and 2068b, so that the position and direction of the holder 2016 with respect tothe base 2056 vary. That is, the holder 2016 moves on the base 2056, sothat its position is adjusted to a predetermined position. That is, theprotruding portions 2068 a and 2068 b function as a holder positionadjusting mechanism for adjusting the position of the holder 2016 on thebasis of the correspondence to the cut-outs formed in the holder bottomplate 2160.

[0246] Since the ball retained in the ball retainer 2062 functions as asliding mechanism when the position of the holder is adjusted, theholder mounting table 2050 can move with the holder 2016. As a result,the force of the air cylinders 2064 a and 2064 b is not so great, theposition of the holder 2016 can be easily adjusted.

[0247] A pair of air cylinder holders 2070 a and 2070 b are mounted onthe bottom face of the holder mounting table 2050 by means of screws2072 a and 2072 b so as to correspond to the opening portions 2057 a and2057 b of the base 2056, respectively. The air cylinder holders 2070 aand 2070 b hold the air cylinders 2074 a and 2074 b, respectively.

[0248] As a result, the air cylinders 2074 a and 2074 b are arranged inthe opening portions 2057 a and 2057 b of the base 2056 so as tocorrespond to the bottom rail portion 2056 b, respectively. Shafts 2076a and 2076 b protrude from the air cylinders 2074 a and 2074 b,respectively, and substantially cylindrical moving pieces 2077 a and2077 b are formed on the tips of the shafts 2076 a and 2076 b,respectively.

[0249] The moving pieces 2077 a and 2077 b are formed of an elasticmaterial of rubber or the like. The shafts 2076 a and 2076 b extend in adirection perpendicular to the principal plane of the base 2056, and themoving pieces 2077 a and 2077 b face the bottom rail portion 2056 b atsmall distances da and db, respectively. Air or nitrogen gas is suppliedto the air cylinders 2074 a and 2074 b (gas piping is not shown), sothat the moving pieces 2077 a and 2077 b connected to the shafts 2076 aand 2076 b can be pushed against or pulled back from the bottom railportion 2056 b by the gas pressure (the distances da and db vary).

[0250] By pushing the moving pieces 2077 a and 2077 b against the bottomrail portion 2056 b, the holder mounting table 2050 can be stopped onthe base 2056. This is based on the fact that the air cylinders 2074 aand 2074 b, to which the moving pieces 2077 a and 2077 b are connected,are fixed to the holder mounting table 2050, and on the other hand, thebottom rail portion 2056 b constitutes a part of the base 2056. Asdescribed above, the air cylinders 2074 a and 2074 b having the movingpieces 2077 a and 2077 b function as a mounting table fixing mechanismfor fixing the holder mounting table 2050 to the base 2056.

[0251] Three plate springs 2078 a, 2078 b and 2078 c are mounted on theside face of the base 2056 by screws 2080 a, 2080 b and 2080 c atsubstantially even intervals, respectively. The plate spring 2078comprises a substantially rectangular fixing portion 2782, two pairs ofelastic portions 2874 a and 2784 b formed on the fixing portion 2782,and elastic portions 2786 a and 2786 b. The elastic portions 2784 a and2784 b contact the side face of the top rail portion 2050 b in thevicinity of their end portions, and the elastic portions 2786 a and 2786b contact the side face of the ball retainer 2062 in the vicinity oftheir end portions, so that a biasing force is applied toward the centerof the base 2056.

[0252] That is, the elastic portions 2784 a and 2784 b function asbiasing means for applying a biasing force to the holder mounting table2050 toward the center of the base 2056, and the elastic portions 2786 aand 2786 b function as biasing means for applying a biasing force to thesliding mechanism (the ball 2060 and the ball retainer 2062) toward thecenter of the base 2056.

[0253] Finally, the three plate springs 2078 a, 2078 b and 2078 cfunction as biasing means for applying a biasing force to both of thesliding mechanism and the holder mounting table 2050 toward the centerof the base 2056 from three directions.

[0254] That is, the three plate plates 2078 a, 2078 b and 2078 cfunction as a mounting table position returning mechanism for returningthe position of the holder mounting table 2050 to a predeterminedposition (the center of the base 2056) and a sliding mechanism returningmechanism for returning the sliding mechanism to a predeterminedposition (the center of the base 2056).

[0255] Between the holder mounting table 2050 and the base 2056, a pairof helical springs 2082 a and 2082 b are provided. The both ends of thehelical springs 2082 a and 2082 b are connected to a substantiallyL-shaped first spring fixture 2084, which is mounted on the outerperiphery of the holder mounting table body 2050 a, and a pair of secondspring fixtures 2086 a and 2086 b which are connected to the base topplate 2056 a so as to surround the tip of the first spring fixture 2084.

[0256] The helical springs 2082 a and 2082 b extend along the outerperiphery of the base 2056 to connect the holder mounting table 2050 tothe base 2056. Therefore, when the holder mounting table 2050 is rotatedwith respect to the base 2056, a biasing force is applied so as toinversely rotate the holder mounting table 2050 with respect to the base2056.

[0257] That is, the helical springs 2082 a and 2082 b function as amounting table angle returning mechanism for intending to return therelative angle of the holder mounting table 2050 with respect to thebase 2056 to the angle before rotation. As a result, in corporation withthe mounting table position returning mechanism, for example, thepositional relationship between the opening portions 2054 a, 2054 b ofthe holder mounting table 2050 and the shafts 2066 a, 2066 b, and thepositional relationship between the air cylinders 2074 a, 2074 b and theopening portions 2057 a, 2057 b of the base 2056 are always maintainedin appropriate states.

[0258] (Conceptual Explanation of First Holder Mounting Portion)

[0259]FIG. 21 is a conceptual view simply showing the construction ofthe first holder mounting portion (boat stage) 2038 shown in FIGS. 16through 20. FIGS. 21A and 21B are top (corresponding to FIG. 16) andpartially sectional (corresponding to FIGS. 17 through 19) views of thefirst holder mounting portion 2038, respectively. The left half of FIG.21B mainly corresponds to FIG. 17, and the right half of FIG. 21Bsubstantially corresponds to FIG. 18.

[0260] Between the holder mounting table 2050 and the base 2056, theball 2060 serving as the sliding mechanism allows movement along theprincipal plane of the holder mounting table 2050 and rotation withrespect to an axis perpendicular to the principal plane.

[0261] The pair of protruding portions 2068 a and 2068 b serving as theholder position adjusting mechanism are arranged so as to be symmetricalwith respect to the center of the base 2056 on the opening portion onthe holder mounting table. The distance between the protruding portions2068 a and 2068 b can be changed by the air cylinders 2064 a and 2064 b.The protruding portions 2086 a and 2086 b enter the pair of cut-outs 166a and 166 b, which are formed in the opening portion 2164 of the holderbottom plate 2160, to adjust the position of the holder 2016.

[0262] The moving piece 2077 of the air cylinder 2074 functions as amounting table fixing mechanism for fixing the holder mounting table2050 to the base 2056. In FIG. 18, the air cylinder 2074 is connected tothe holder mounting table 2050, whereas in FIG. 21, the air cylinder2074 is fixed to the base 2056. The difference between FIGS. 18 and 21is based on the fact that the former regards space saving as importantand the latter regards facilitation of understanding as important. Evenif the air cylinder 2074 is fixed to any one of the holder mountingtable 2050 and the base 2056, the moving piece 2077 blocks the relativemovement between the holder mounting table 2050 and the base 2056.

[0263] Each of the three springs 2078 a, 2078 b and 2078 c functions asa biasing means for applying a biasing force to the holder mountingtable 2050 in three directions toward the center of the base 2056. Thesethree plate springs 2078 a, 2078 b and 20768 c function as a mountingtable position returning mechanism for returning the position of theholder mounting table, as a whole.

[0264] The pair of springs 2082 a and 2082 b function as a mountingtable angle returning mechanism for returning the angular relationshipbetween the holder mounting table and the base 2056.

[0265] (Procedure for Transferring Objects to Holder)

[0266] The procedure for transferring wafers W to the holder 2016 on thefirst holder mounting portion (boat stage) will be described below indetail. FIGS. 22 through 27 are schematic diagrams showing the state ofthe first holder mounting portion in this procedure, and FIG. 28 is aflow chart showing the transfer procedure.

[0267] (1) The holder mounting table 2050 (FIG. 22), on which the holder2016 has not been mounted, is mounted on the holder 2016 (step S10 andFIG. 23).

[0268] The mounting of the holder 2016 on the holder mounting table 2050is carried out by the above described holder transfer mechanism 2042(see FIG. 15). At this time, there is some possibility that the centerC2 of the mounted holder 2016 may be shifted from the center (referenceposition of holder to be transferred) C1 of the base 2056, so that thecenter C1 of the base 2056 may not be coincident with the center C2 ofthe holder 2016.

[0269] Furthermore, before the transfer of the holder 2016, it isassumed that the holder position adjusting mechanism (the protrudingportion 2068 and the air cylinder 2064) and the mounting table fixingmechanism (the moving piece 2077 and the air cylinder 2074) remain beingreleased.

[0270] (2) The position of the holder is adjusted by the holder positionadjusting mechanism (the protruding portion 2068 and the air cylinder2064) (step S11 and FIG. 24).

[0271] The pair of protruding portions 2068 are moved so as to increasethe distance therebetween. Although the pair of protruding portions 2068may be moved at different times, the pair of protruding portions 2068are preferably simultaneously moved in view of the operation time.

[0272] The pair of protruding portions 2068 enter the tips of the pairof cut-outs 166 a and 166 b, which are formed in the opening portion2164 of the holder bottom plate 2160, respectively, so that the positionof the holder 2016 is adjusted (engagement of the cut-outs 166 with theprotruding portions 2068). For example, the tips of the cut-outs 166 aand 166 b are set to be symmetrical with respect to the center of theholder bottom plate 2160, and the pair of protruding portions 2068 aremoved to positions, which are symmetrical with respect to the center ofthe base 2056, respectively, so that the center C1 of the holder 2016can be coincident with the center C2 of the base 2056.

[0273] Since the holder mounting table 2050 can slide the base 2056 tomove with the holder 2016, it is possible to quickly move the holder2016 without any strong forces.

[0274] (3) The holder mounting table 2050 is fixed to the base 2056 bythe mounting table fixing mechanism (the moving piece 2077 and the aircylinder 2074) (step S12).

[0275] This fixing is carried out by pushing the moving piece 2077against the holder mounting table 2050 or the base 2056 by means of theair cylinder which is fixed to the holder mounting table 2050 or thebase 2056.

[0276] This fixing step is carried out prior to step S13 in order tosurely prevent the movement of the holder mounting table 2050 during thetransfer of the wafers W at the next step S13.

[0277] If it is possible to prevent the movement of the holder 2016 bymeans of the protruding portions 2068 and the cut-outs 166, this fixingmay be carried out immediately before the release of the adjustment ofthe position of the holder at a subsequent step S14. The reason why thefixing of the holder mounting table 2050 is carried out prior to stepS14 is that it is required to prevent the movement of the holdermounting table 2050 during the release of the adjustment of the positionof the holder.

[0278] (4) The wafers W are transferred to the holder 2016 which ismounted on the holder mounting table 2050 (step S13 and FIG. 25).

[0279] The wafers W serving as the objects to be treated are transferredand held so that their edge portions are inserted into the grooves whichare formed in the support of the holder 2016. This transfer is carriedout by means of the above described transfer mechanism 2044 (see FIG.15).

[0280] Since the position of the holder 2016 has been adjusted at stepS11 prior to this transfer, the wafers W serving as the objects to betreated can be precisely transferred to the holder 2016 (the control ofthe positional relationship between the wafers W and the holder 2016).

[0281] By precisely controlling the positions of the wafers W withrespect to the holder 2016, it is possible to easily ensure theuniformity of the heat treatment on the wafers W. On the other hand, ifthe precision of the position of the installed holder 2016 is bad, it isconsidered that it is not only difficult to ensure the uniformity of theheat treatment on the wafers W, but it is also possible to insert thewafers W into the grooves of the support of the holder 2016.

[0282] (5) The holder position adjusting mechanism is released (stepS14).

[0283] That is, the pair of protruding portions 2068 are moved towardthe center of the base 2056 by the action of the air cylinder 2064, andthe engagement with the holder bottom plate 2160 of the cut-outs 166 isreleased. At this time, the movement of the holder mounting table 2050is blocked by the action of the mounting table fixing mechanism (themoving piece 2077 and the air cylinder 2074).

[0284] (6) The holder 2016 is removed from the holder mounting table2050 (step S15 and FIG. 26).

[0285] Also at this time similar to step S14, the movement of the holdermounting table 2050 is blocked by the action of the mounting tablefixing mechanism (the moving piece 2077 and the air cylinder 2074).

[0286] (7) The mounting table fixing mechanism (the moving piece 2077and the air cylinder 2074) is released to allow the holder mountingtable 2050 to relatively move with respect to the base 2056 (step S16).That is, the moving piece 2077 does not contact the holder mountingtable 2050 or the base 2056 by the action of the air cylinder 2074, sothat the holder mounting table 2050 can be easily moved by the action ofthe sliding mechanism (the ball 2060).

[0287] Thereafter, the center of the holder mounting table 2050 iscoincident with the center C1 of the base 2056 by the action of themounting table position returning mechanism (the springs 2078 a, 2078 band 2078 c) and the mounting table angle returning mechanism (thesprings 2082 a and 2082 b), so that the state of the holder mountingtable 2050 returns to the stage before the holder is mounted thereon(FIG. 15) (step S17 and FIG. 27).

[0288] Since the position of the holder mounting table 2050 before themounting of the holder always returns to the same place, the amount ofthe movement of the holder mounting table 2050 with the adjustment ofthe position of the holder 2016 can be ensured at step S11.

[0289] On the other hand, if the position of the holder mounting table2050 does not return, when the position of the holder 2016 mounted onthe holder mounting table 2050 is shifted in the same direction as thelast mounting of the holder, there is some possibility that the holdermounting table 2050 can not sufficiently be moved.

[0290] As described above, the holder mounting portion (boat stage)according to the present invention has the holder position adjustingmechanism for adjusting the position of the holder to a predeterminedposition, so that it is possible to precisely transfer and hold theobjects to and in the holder.

[0291] [Other Preferred Embodiments]

[0292] The above described preferred embodiments can be extended andchanged, and the extended and changed preferred embodiments should beincluded in the technical scope of the present invention.

[0293] (1) While the first holder mounting portion (boat stage) has beena part of the heat treatment system in the above described preferredembodiments, the first holder mounting portion may be separated from theheat treatment system. For example, the objects to be treated may betransferred to the holder in the holder mounting portion outside of theheat treatment system, and thereafter, the holder to which the objectsto be treated have been completely transferred may be transferred to theheat treatment system to carry out a heat treatment therein.

[0294] (2) The sliding mechanism should not limited to the combinationof the ball and the retainer for retaining the ball. For example, anymeans for reducing friction between the holder mounting table and thebase, such as lubricant, may be used. In addition, the sliding mechanismmay be fixed to any one of the holder mounting table and the base.

[0295] (3) The holder position adjusting mechanism should not be limitedto the combination of the protruding portion and the air cylinderconnected to the protruding portion. The means for moving the protrudingportion should not be limited to the air cylinder. For example, anelectric means, such as an electric motor, may be used.

[0296] The place of the cut-outs corresponding to the protrudingportions should not be limited to the opening portion formed in theholder bottom plate. For example, the cut-outs may be formed in theouter peripheral portion of the holder bottom plate. In this case, thedistance between the protruding portions decreases, so that the cut-outsengage the protruding portions.

[0297] The shapes of the protruding portions and the cut-outs of theholder mounting table should not be limited to the cylindrical shape andthe substantially triangular shape, respectively, if the protrudingportions can engage the cut-outs. For example, if recessed portions areprovided in place of the protruding portions and if the holder isprovided with protruding portion in place of the cut-outs, the positionof the holder can be adjusted by the engagement of the recessed portionswith the protruding portions.

[0298] In addition, the number of the protruding portions should not belimited to two. The numbers of the cut-outs and the correspondingprotruding portions may be three or more, respectively. For example, ifthree protruding portions are arranged on a circumstance and if theseprotruding portions move so as to approach or leave the center of thecircumstance, the protruding portions can engage the cut-outs.

[0299] Moreover, while both of the pair of protruding portions have beenmoved in the above described preferred embodiments, one of theprotruding portions may be fixed and only the other protruding portionmay be moved to adjust the position of the holder.

[0300] (4) The components of the mounting table position returningmechanism or mounting table angle returning mechanism should not belimited to the plate springs or the helical springs. For example,electric means or air may be used as the biasing means.

[0301] The number of the biasing means constituting the mounting tableposition returning mechanism should not be limited to three. Forexample, the biasing force toward the same center may be applied to theholder mounting table by four or more biasing means.

[0302] Similarly, the mounting table angle returning mechanism shouldnot be limited to the two biasing means. For example, the mounting tableangle returning mechanism may comprises three or more biasing means.

[0303] In short, the mounting table position returning mechanism or themounting table angle returning mechanism may be any means for applyingforce to return the position or angle of the holder mounting table to apredetermined position or angle if the position or angle of the holdermounting table is shifted from the predetermined position or angle. Forexample, the mounting table position returning mechanism or the mountingtable angle returning mechanism may be based on a magnetic force.

[0304] (5) The mounting table fixing mechanism should not be limited tothe combination of the air cylinder and the moving piece in the abovedescribed preferred embodiments. The means for moving the moving pieceshould not be limited to the air cylinder. For example, the means formoving the moving piece may be electric means, such as an electricmotor.

[0305] As described above, the air cylinder may be fixed to any one ofthe holder mounting table and the base, or may be connected to a quitedifferent another component of the heat treatment system.

[0306] The shape and material of the moving piece may be suitablychanged.

[0307] The objects to be treated, which have been transferred to theholder on the holder mounting portion according to the third invention,are to be heat-treated by the heat treatment system while being held inthe holder. At this time, since the objects to be treated are preciselyheld in the holder, the objects to be treated are precisely transferredto the holder, so that the objects to be treated can be more uniformlyheat-treated.

[0308] Referring to the accompanying drawings, the fourth invention willbe described below in detail.

[0309] Referring to the accompanying drawings, a preferred embodiment ofthe fourth invention will be described below.

[0310]FIG. 29 is a perspective view of a preferred embodiment of avertical heat treatment system according to the fourth invention, andFIG. 30 is a perspective view of this vertical heat treatment systemviewed from a different angle from that in FIG. 29.

[0311] As shown in these figures, the vertical heat treatment system3001 is a system capable of carrying out various heat treatments, suchas diffusion, oxidation or CVD, with respect to wafers W. The interiorof a casing 2010 defining the contour of the vertical heat treatmentsystem 3001 is separated by partition walls 3012 and 3013 into a carriertransfer area Sa, a loading area (loading chamber) Sb and a heattreatment area Sc.

[0312] In the loading area Sb, the transfer of wafers W from theinterior of a carrier 3014 to a wafer boat 3016, and the carrying of thewafer boat 3016 in and out of a heat treatment furnace 3018 are carriedout. Clean air is supplied to the carrier transfer area Sa via a filter(not shown), so that the carrier transfer area Sa is maintained in anatmosphere of atmospheric air. The loading area Sb is separated as anairtight region in which an atmosphere of nitrogen gas (an atmosphere ofan inert gas or non-oxygen) is formed.

[0313] The carrier 3014 is a so-called closed type carrier, which housestherein a plurality of wafers W and which is closed by an FIMS(Front-opening Interface Mechanical Standard) door 3015. Specifically,the carrier 3014 is a portable plastic vessel capable of housing thereina plurality of, e.g., about 13 to 25, semiconductor wafers w having apredetermined diameter, e.g., a diameter of 300 mm, in a horizontalstate on multiple stages at regular intervals in vertical directions.Moreover, the carrier 3014 is formed with an outlet for the wafers W inthe front face portion thereof, and is detachably provided with the FIMSdoor 3015 for airtightly closing the outlet.

[0314] The front face portion of the casing 3010 is provided with acarrier carrying-in/out opening 3020 for carrying the carrier 3014 inand out by means of an operator or a transfer robot. The carriercarrying-in/out opening 3020 is provided with a load port 3022 forcarrying the carrier 3014 in or out of the carrier transfer area Sa. Bymeans of a transfer mechanism 3024 provided on the load port 3022, thecarrier 3014 is moved on the load port 3022 to be transferred to theinterior of the carrier transfer area Sa.

[0315] In the carrier transfer area Sa, shelf-like storage portions 3026for storing a plurality of carriers 3014 are provided above the loadport 3022 and above the side of the partition wall 3012. On the side ofthe partition wall 3012 in the carrier transfer area Sa, a carriermounting portion (FIMS port) 3027 is provided for supporting thereon thecarrier 3014 to transfer the wafers. In the carrier transfer area Sa, acarrier transfer mechanism 3028 is provided for transferring the carrier3014 between the load port 3022, the storage portion 3026 and thecarrier mounting portion 3027.

[0316] The carrier transfer mechanism 3028 comprises: a liftingmechanism 3028 a which is provided on one side portion of the carriertransfer area Sa; a lifting arm 3028 b which is vertically moved by thelifting mechanism 3028 a; an arm 3028 c which is provided on the liftingarm 3028 b; and a transfer arm 3028 d which is provided on the arm 3028c for supporting thereon the bottom of the carrier 3014 to transfer thecarrier 3014. The partition wall 3012 is provided with a door 3030 whichis formed so as to have a shape corresponding to the wafer outlet of thecarrier 3014 and which is capable of being open and closed. By openingthe door 3030 while the carrier 3014 contacts the door 3030, the wafersW in the carrier 3014 can be taken in and out of the loading area Sb.

[0317] In the heat treatment area Sc, there is provided the heattreatment furnace 3018 for housing therein the wafer boat 3016, whichholds the wafers W, to carry out a predetermined heat treatment.

[0318] Above the inside of the loading area Sb, a lid 3032 is providedso as to be capable of being vertically moved by a boat elevator 3034which is a lifting mechanism. The lid 3032 can support thereon theholder 3016 of, e.g., quartz, which holds a plurality of, e.g., about100 to 150, wafers Won multiple stages at regular intervals in verticaldirections. By vertically moving the lid 2032 by means of the liftingmechanism 3024, the wafer boat 3016 holding the wafers W can be carriedin and out of the heat treatment chamber of the heat treatment furnace3018. In the vicinity of the throat of the heat treatment furnace 3018,there is provided a shutter 3026 which is capable of being open andclosed in horizontal directions for closing the throat when the lid 3032is moved downwards and when the boat 3016 is carried out after the heattreatment.

[0319] In one side portion of the loading area Sb, a boat stage 3038which is a boat mounting portion is provided for supporting thereon thewafer boat 3016 in order to the wafers W. Behind the boat stage 3038, astandby stage 3040 is provided for supporting thereon the wafer boat3016 which holds the wafers W.

[0320] In the lower portion of the loading area Sb, a boat transfermechanism 3042 is provided between the carrier mounting portion 3027 andthe boat elevator 3034 for transferring the wafer boat 3016 between theboat stage 3038, the standby stage 3040 and the lid 3032.

[0321] The boat transfer mechanism 3042 comprises a first arm 3042 acapable of being rotated in horizontal directions and moved in verticaldirections, and a supporting arm 3042 b which is supported on the tipportion of the first arm 3014 a so as to be rotatable in horizontaldirections and which is capable of supporting the boat 3016 in verticaldirections, the supporting arm 3042 b having a substantially C-shapedopening. Above the boat transfer mechanism 3042, a transfer mechanism3044 is provided for transferring the wafers W between the carrier 3014on the carrier transfer portion 3027 and the wafer boat 3016 on the boatstage 3038.

[0322] The transfer mechanism 3044 comprises a lifting mechanism 3044 a,a first arm 3044 b which is connected to the lifting mechanism 3044 aand which is rotatable in horizontal directions, a second arm 3044 cwhich is connected to the first arm 3044 b and which is rotatable inhorizontal directions, and a supporting arm 3044 d which is provided onthe second arm 3044 c and which is retractable. The supporting arm 3044d comprises a plurality of, e.g., two to five, fork-shaped thin plates,and is movable while supporting thereon the wafers W.

[0323] The loading area Sb will be described below in detail.

[0324] The casing 3010 constituting the loading area Sb is provided withan air intake valve 3051, which is provided for introducing air, and anexhaust value 3052 which is connected to a nitrogen gas exhaust pipe(not shown), in order to replace the atmosphere of nitrogen gas at apositive pressure with an atmosphere of atmospheric air in the loadingarea Sb, which is separated as the airtight region by the partitionwalls 3012 and 3013 in the casing 3010, during the maintenance of thesystem or the like.

[0325] In this preferred embodiment, an atmosphere of nitrogen gascontaining oxygen having a concentration of, e.g., 30 ppm or less, isformed by closing the valves 3051 and 3051 and introducing nitrogen gas.As shown in FIG. 31, this concentration of oxygen is sampled anddetected by an oxygen analyzer (not shown) from an oxygen concentrationsampling port 3054 a.

[0326] The vertical heat treatment system 3001 in this preferredembodiment is provided with a safety mechanism utilizing an O₂ sensor3054 which is provided in the loading area Sb, in order to prevent theoperator from erroneously entering the loading area Sb in the state thatthe atmosphere of nitrogen gas is formed in the loading area Sb, i.e.,in the state that the concentration of oxygen in the area Sb is low,during the maintenance of the system or the like.

[0327] That is, as shown in FIGS. 32 and 33, the safety mechanism 3055is designed to control the opening and closing (locking/unlocking) of amaintenance door 3056 (see FIG. 30) which is provided on the back faceof the heat treatment system 3001. The safety mechanism 3055 isincorporated into the casing 3010 of the system body, and is anelectromagnetic locking mechanism to which a control signal based on theconcentration of oxygen detected by the O₂ sensor 3054 is inputted via asignal line 3057. By this control signal, the protruding/non-protrudingof a lock pin 3058, which is engageable with a recessed portion 3060 aformed in the maintenance door 3056, is controlled.

[0328] For example, when it is detected by the O₂ sensor that theconcentration of oxygen in the loading area Sb is 19.5% or less, thelock pin 3058 protrudes toward the maintenance door 3056 (engages therecessed portion 3060 a), so that the locking state of the maintenancedoor 3056 is maintained. In this case, of course, even if a knob 3059 isrotated, the door 3056 is not open. On the other hand, when it isdetected by the O₂ sensor that the concentration of oxygen in theloading area Sb is 19.5% or more, the lock pin 3058 is retracted fromthe maintenance door 3056 to be in a non-protruding state (in which thelock pin 3058 does not engage the recessed portion 3060 a), so that themaintenance door 3056 is in an unlocked state in which the maintenancedoor 3056 can be open.

[0329] The safety mechanism 3055 has a fail safe function, and isconnected to a main control part (not shown) for generally controllingthe of the system. That is, if the main control part detects that thesystem itself does not normally operate for some reason, the lock pin3058 is maintained in the locking state even if it is detected that theconcentration of oxygen in the area Sa is 19.5% or more.

[0330] The safety mechanism 3055 is also provided with a key portion3060 for forcing to release the locking state on the assumption that anemergency situation may occur, regardless of the kind of the controlsignal based on the concentration of oxygen, which is inputted via thesignal line 3057. Furthermore, of course, if a maintenance door isprovided on the side face of the casing of the heat treatment system,such a safety mechanism may be applied to this door.

[0331] Referring to FIGS. 31, 34 and 35, a gas circulating coolingmechanism provided in the loading area Sb of the vertical heat treatmentsystem 3001 in this preferred embodiment will be described below.Furthermore, FIG. 31 is a perspective view showing the structure of thegas circulating cooling mechanism 3061 viewed from the back face side ofthe system 1. In addition, FIG. 34 is a sectional view showing a topradiator 3066 and a bottom radiator 3070, which constitute the gascirculating cooling mechanism 3061, viewed from the side of a surfacefacing an FFU (Filter Fan Unit) 3065, and FIG. 35 is a viewschematically showing the flow of nitrogen gas by the gas circulatingcooling mechanism 3061.

[0332] As shown in these figures, the gas circulating cooling mechanism3061 is provided in the loading area Sb which has a closed structure (N₂purge box structure) in which an airtight region is formed by anatmosphere of nitrogen gas. That is, the gas circulating coolingmechanism 3061 comprises: the FFU 3065 which has a ventilating port 3063in the vicinity of a throat of the bottom of the heat treatment 3018arranged above the loading area Sb and which has a filter 3064 forpurifying and sending nitrogen gas to the vicinity of the throat 3062from the side via the ventilating port 3063; the top radiator 3066 whichis arranged so as to face the ventilating port 3063 in the vicinity ofthe throat 3062; intake fans 3067 and 3068 for sucking nitrogen gas inthe vicinity of the throat 3062 via the top radiator 3066; a circulatingduct 3053 which forms a nitrogen gas circulating path between the intakefuns 3067, 3068 and the FFU 3065 so that nitrogen gas sucked by theintake funs 3067 and 3068 is returned to the FFU 3065 and which ispartially arranged below the loading area Sb; an intake port 3069 whichis formed in a region of the circulating duct 3053 arranged below thearea Sb so that a part of nitrogen gas sent by the FFU 3065 is suckedbelow the loading area Sb; and the bottom radiator 3070 which isarranged in the circulating duct 3053 between the intake port 3069 andthe filter 3064 so as to cool nitrogen gas drawn into the circulatingduct 3053 from the intake funs 3057, 3068 and the intake port 3069 tojoin.

[0333] The filter 3064 of the FFU 3065 comprises a filter for particle,which filters and collects particulate impurities in nitrogen gas.Moreover, the FFU 3065 is provided with a blower fan 3071 upstream ofthe filter 3064 in the flow of nitrogen gas, i.e., below the loadingarea Sb, in order to substantially send nitrogen gas from theventilating port 3063 via the filter 3064.

[0334] As shown in FIG. 34, the top radiator 3066 and the bottomradiator 3070 are made of stainless to inhibit impurities from adheringto the wafers W to cause a chemical reaction (chemical contamination) orthe like. In the top radiator 3066, only a principal part of a pipe 3072substantially having a cooling effect is exposed from the inner wall(side wall) of the casing 3010 in the loading area Sb so that waterdroplets do not adhere to the wafers W.

[0335] The pipe 3072 of the top radiator 3066 and a pipe 3073 providedin the bottom radiator 3070 are connected to each other by means of aconnecting pipe 3074. A refrigerant for removing heat from temperatureraised nitrogen gas passes through the pipes 3072, 3073 and theconnecting pipe 3074. In order to increase the quantity of heatexchange, the refrigerant preferably flows in the top radiator 3066 andthe bottom radiator 3070 in parallel. Moreover, on the surface of thepipes 3072 and 3073, a plurality of plate-shaped fins 3075 and 3076 areconnected so as to be perpendicular to the axes of the pipes.

[0336] As shown in FIGS. 33 and 34, the circulating duct 3053 mainlycomprises: a pipe portion 3053 a for transferring nitrogen gas, which isintroduced into the top radiator 3066 via its front face, from the sideportion of the radiator 3066 to the top; a pipe portion 3053 b forguiding nitrogen gas from the pipe portion 3053 a toward the intake port30, i.e., below the loading area Sb; and a pipe portion 3053 c, arrangedbelow the area Sb, for supplying nitrogen gas, which is transferred fromthe pipe portion 3053 b, and nitrogen gas, which joins by the intakeport 3069, to the FFU 3065.

[0337] That is, as shown in FIGS. 31 and 35, in the gas circulatingcooling mechanism 3062 with this construction, nitrogen gas, which issent in the direction of arrow A from the ventilating port 3063 of theFFU 3065, i.e., to the vicinity of the throat 3062, passes over the topradiator 3066 to be sucked in the direction of arrow C from thedownstream of the top radiator 3066 by means of the intake fans 3067 and3068. Moreover, this nitrogen gas passes through the pipe portions 3053a and 3053 b to be transferred in order of arrows C, D, E and F.

[0338] On the other hand, a part of nitrogen gas, which is sent in thedirection of arrow A by means of the FFU 3065, travels directly towardthe lower portion of the loading area Sb to be transferred in directionsof arrows B1 and C1 to be sucked via the intake port 3069. Moreover,nitrogen gas downstream of the intake port 3069, i.e., nitrogen gasjoining in the pipe portion 3053 c, flows in the direction of arrow G topass through the bottom radiator 3070 to flow in the direction of arrowH to return to the FFU 3065.

[0339] As described above, the gas circulating cooling mechanism 3061 ofthe vertical heat treatment system 3011 in this preferred embodimentmainly comprises: the FFU 3065 for sending nitrogen gas to the vicinityof the throat 3062 through which the heat-treated wafers W are carriedout; the top radiator 3066 for removing heat of temperature-raisednitrogen gas in the vicinity of the throat 3062; and the intake funs3067 and 3068 for sucking nitrogen gas in the vicinity of the throat3062 over the heat exchanger. Therefore, for example, when the wafers Wheated to a high temperature in the heat treatment furnace 3018 arecarried out, temperature-raised nitrogen gas in the vicinity of thethroat 3062 can be positively drawn toward the top radiator 3062 bymeans of the intake funs 3067 and 3068 to remove the heat to cool thevicinity of the throat 3062 of the heat treatment furnace 3018.Therefore, heat emitted from the throat 3062 of the heat treatmentfurnace 3016 can be effectively removed, and the heated wafers W can becooled. Thus, it is not feared that the temperature of the loading areaSb suddenly rises, so that it is possible to inhibit control parts,which are provided in the loading area Sb, e.g., which constitute aloading mechanism, from being damaged by heat.

[0340] In the gas circulating cooling mechanism 3061, the intake funs3067 and 3068 are arranged downstream of the top radiator 3066 in theflow of nitrogen gas, so that nitrogen gas passing through the topradiator 3066 to be cooled is sucked by the intake funs 3067 and 3068.Thus, it is possible to inhibit the intake funs 3067 and 3068 from beingdamaged by heat. Moreover, in the gas circulating cooling mechanism3062, the flow of nitrogen gas is regulated above the loading area Sb bythe intake funs 3067, 3068 and the duct 3053, and the intake port 3069,which is another intake portion, is provided below the loading area Sbto similarly regulate the flow of nitrogen gas, so that it is possibleto provide excellent cooling effects while inhibiting particles fromflying in the area Sb.

[0341] While the present invention has been specifically described interms of the preferred embodiments, the present invention should not belimited to the above described preferred embodiments, but the inventioncan be modified in various ways without departing from the gist of theinvention. For example, a glass substrate or an LCD substrate, otherthan the wafer, may be used as the object to be treated.

[0342] As described above, the heat treatment system according to thefourth invention mainly comprises a ventilating unit for sending aninert gas to the vicinity of the throat, through which the heat-treatedobjects are carried out, a heat exchanger for removing heat of atemperature-raised cooling fluid after the heat treatment, and an intakefun for sucking the cooling fluid in the vicinity of the throat over theheat exchanger. Thus, for example, when the objects heated to a hightemperature in the heat treatment furnace are carried out, the coolingfluid is blown onto the objects, and the temperature-raised coolingfluid in the vicinity of the throat is positively drawn toward the heatexchanger by the intake fun, so that the heat can be removed to cool thecooling fluid, the objects and the vicinity of the throat of the heattreatment furnace.

[0343] Therefore, according to the heat treatment system according tothe fourth invention, it is possible to effectively remove heat emittedfrom the throat of the heat treatment furnace, and it is possible tocool the heated objects. Therefore, it is not feared that thetemperature in a carrying-in/out region, in which the objects arecarried in and out of the heat treatment furnace, suddenly rises, sothat it is possible to inhibit control parts, which is provided in thecarrying-in/out region, from being damaged by head, and it is possibleto shorten the transfer time of the objects and improve throughput.

1. A vertical heat treatment system for carrying an object to betreated, which is housed in a treating-object housing box closed by anopening/closing lid, in a treating-object transfer area via an opening,which is formed in a partition wall separating a housing-box transferarea for transferring the treating-object housing box from thetreating-object transfer area in an atmosphere of an inert gas, to carryout a predetermined treatment, wherein standby box transfer means isprovided in said housing-box transfer area for holding a treating-objecthousing box, which houses therein the next object to be carried in saidtreating-object transfer area, in the vicinity of said opening to causesaid treating-object housing box to stand by.
 2. A vertical heattreatment system as set forth in claim 1, wherein in said housing-boxtransfer area, there is provided a stocker portion for temporarilystoring therein said treating-object housing box, and a box transfer armfor transferring said treating-object housing box in said stockerportion to a mounting table which is provided in said opening.
 3. Avertical heat treatment system as set forth in claim 1, wherein anopening/closing door is provided in said opening, and an opening/closingmechanism for removing said opening/closing door and saidopening/closing lid to cause said opening/closing door and saidopening/closing lid to take shelter is provided in said treating-objecttransfer area.
 4. A vertical heat treatment system comprising: a liftingmechanism which is vertically moved for carrying a holder, in which anobject to be treated is held, in and out of a heat treatment furnace; aholder mounting portion for mounting thereon the holder to transfer theobject; a holder transfer mechanism for transferring the holder betweenthe lifting mechanism and the holder mounting portion; and atreating-object transfer mechanism for transferring the object to theholder which is supported on the holder transferring portion, thetreating-object transfer mechanism having a motion space region whichoverlaps with a motion space region of the holder transfer mechanism,wherein said treating-object transfer mechanism comprises a swivel armsupported so as to be rotatable about a vertically extending rotationcenter shaft, and a transfer head provided on the tip portion of theswivel arm so as to be rotatable on a horizontal plane, and furthercomprises driving means having the sheltering function of moving thetransfer head of the treating-object transfer mechanism on thehorizontal plane along the outer peripheral edge of the liftingmechanism, which is positioned at a lower position, to cause thetransfer head to take shelter on a side face portion of a housing.
 5. Avertical heat treatment system as set forth in claim 4, wherein thesheltering function of the driving means of the treating-object transfermechanism causes the transfer head of the treating-object transfermechanism to revolve around the rotation center shaft of the swivel armwhile causing the transfer head itself to rotate on its axis in theopposite direction to the direction of rotation of the transfer head, tocause the transfer head to take shelter on the side face portion in thehousing.
 6. A vertical heat treatment system as set forth in claim 4,wherein the sheltering function of the driving means of thetreating-object transfer mechanism operates the transfer head of thetreating-object transfer mechanism from a state that the transfer headis positioned at a reference position in its motion space region.
 7. Avertical heat treatment system as set forth in claim 4, wherein thedriving means of the treating-object transfer mechanism comprises astretching mechanism for rotating the swivel arm, and a belttransmission mechanism for transmitting the rotational motion of theswivel arm to the transfer head.
 8. A vertical heat treatment system asset forth in claim 4, wherein the reference position in the motion spaceregion is set by a pulley ratio in the belt transmission mechanism.
 9. Amethod for controlling a vertical heat treatment system comprising: alifting mechanism which is vertically moved for carrying a holder, inwhich an object to be treated is held, in and out of a heat treatmentfurnace; a holder mounting portion for mounting thereon the holder totransfer the object; a holder transfer mechanism for transferring theholder between the lifting mechanism and the holder mounting portion;and a treating-object transfer mechanism for transferring the object tothe holder which is supported on the holder transferring portion, thetreating-object transfer mechanism having a motion space region whichoverlaps with a motion space region of the holder transfer mechanism,the treating-object transfer mechanism comprising a swivel arm supportedso as to be rotatable about a vertically extending rotation centershaft, and a transfer head provided on the tip portion of the swivel armso as to be rotatable on a horizontal plane, wherein the transfer headof the treating-object transfer mechanism is moved on the horizontalplane along the outer peripheral edge of the lifting mechanism, which ispositioned at a lower position, to take shelter on a side face portionof a housing, when the holder transfer mechanism is operated.
 10. Amethod for controlling a vertical heat treatment system as set forth inclaim 9, wherein the transfer head of the treating-object transfermechanism is caused to revolve around the rotation center shaft of theswivel arm while the transfer head itself is caused to rotate on itsaxis in the opposite direction to the direction of rotation of thetransfer head, to take shelter on the side face portion in the housing.11. A vertical heat treatment system having a holder supportingmechanism comprising: a holder mounting table for mounting thereon aholder for holding a plurality of objects to be heat-treated, in astacked state; and a holder position adjusting mechanism including aplurality of protruding portions corresponding to the shape of a bottomplate of the holder, and a distance varying mechanism for varying thedistance between the plurality of protruding portions.
 12. A verticalheat treatment system as set forth in claim 11, wherein said holdersupporting mechanism further comprises a sliding mechanism for allowingsaid holder mounting table to move on a plane along a holder mountingsurface of said holder mounting table.
 13. A vertical heat treatmentsystem as set forth in claim 11, wherein said holder supportingmechanism further comprises a returning mechanism for returning saidholder mounting table to a predetermined position, said returningmechanism including biasing means for biasing said holder mounting tablein a different direction on a plane along a holder mounting surface ofsaid holder mounting table.
 14. A method for transferring an object tobe treated, said method comprising: a mounting step of causing a holder,which serves to hold a plurality of objects to be heat-treated in astacked state, to be mounted on a holder mounting table; a positioningstep of moving said holder, which is mounted on said holder mountingtable at said mounting step, together with said holder mounting table,on a plane along a holder mounting surface of said holder mounting tableto position said holder at a predetermined position; a transfer step oftransferring said objects to said holder which is positioned at saidpositioning step; and a returning step of removing said holder, to whichsaid objects are transferred at said transfer step, from said holdermounting table to return said holder mounting table to a predeterminedposition.
 15. A heat treatment system comprising: a heat treatmentfurnace for heat-treating an object to be treated; a throat which isprovided in said heat treatment furnace for carrying said object in andout; and a cooling mechanism for cooling the vicinity of said throat.16. A heat treatment system as set forth in claim 15, wherein saidcooling mechanism comprises a ventilating unit having a ventilating portfor sending a cooling fluid toward the vicinity of said throat, and aheat exchanger arranged so as to face said ventilating port in thevicinity of said throat.
 17. A heat treatment system as set forth inclaim 16, wherein said cooling mechanism further comprises an intake fanfor sucking the cooling fluid in the vicinity of said throat over saidheat exchanger.
 18. A heat treatment system as set forth in claim 17,wherein said cooling mechanism further comprises: a duct for forming acirculating path for said cooling fluid between said intake fun and saidventilating unit so that said cooling fluid sucked by said intake fanreturns to said ventilating unit; a filter, provided in said duct orsaid ventilating unit, for purifying said cooling fluid which is sent bysaid ventilating unit; and an intake port which is formed on said ductat least upstream of said filter so that said cooling fluid sent by saidventilating unit is sucked at a different position from a position atwhich said cooling fluid is sucked by said intake fun.
 19. A heattreatment system as set forth in claim 18, wherein said coolingmechanism further comprises a second heat exchanger which is arranged insaid duct between said intake port and said filter so as to cool thecooling fluid which is drawn into said duct from said intake fan andsaid intake port to join.
 20. A heat treatment system having a loadingchamber in which a mechanism for carrying an object to be treated in andout of a throat of a bottom portion of a heat treatment furnace andwhich has a loading chamber separated as an airtight region, whereinsaid throat of said bottom portion of said heat treatment furnace isarranged above said loading chamber, said loading chamber including: aventilating unit which has a ventilating port in the vicinity of saidthroat and a filter for purifying and sending a cooling fluid from theventilating port to the vicinity of said throat from the side; a firstheat exchanger which is arranged so as to face said ventilating port inthe vicinity of said throat; an intake fan for sucking the cooling fluidin the vicinity of said throat over said first heat exchanger; acirculating duct which forms a circulating path for said cooling fluidbetween said intake fan and said ventilating unit so that said coolingfluid sucked by said intake fan returns to said ventilating unit, atleast a part of sand circulating duct being arranged below said loadingchamber; an intake port which is formed in the part of said circulatingduct below said loading chamber so that a part of said cooling fluidsent by said ventilating unit is sucked below said loading chamber; anda second heat exchanger which is arranged in said circulating ductbetween said intake port and said filter so that the cooling fluid drawninto said circulating duct from said intake fan and said intake port tojoin is cooled.
 21. A method for cooling a loading chamber which isprovided with a mechanism for carrying an object to be treated in or outof a throat of a heat treatment furnace in a heat treatment system andwhich is separated as an airtight region, said method comprising thesteps of: purifying and sending said cooling fluid to the vicinity ofsaid throat of said heat treatment furnace; sucking said cooling fluid,which is sent to the vicinity of said throat, over a heat exchanger,which is arranged in the vicinity of said throat, by means of an intakefan to drawn said cooling fluid into a duct which is formed as acirculating path for returning said cooling fluid; sucking said coolingfluid, which is sent by said ventilating unit, at a different positionfrom a position at which said cooling fluid is sucked by said intakefun, by means of an intake port which is formed on said duct; andcooling said cooling fluid, which is drawn into said duct from saidintake fun and said intake port to join, by means of a second heatexchanger, which is arranged in said duct downstream of said intakeport, to return the cooled cooling fluid to said ventilating unit,wherein said steps are continuously carried out in a process forcarrying said object out of at least said throat of said heat treatmentfurnace.